Nanospheres of sec14-like proteins and cognate ligands

ABSTRACT

The present invention relates to a nanosphere comprising an equal number of a human SEC 14-like protein and a cognate ligand of said SEC 14-like protein as well as to methods of producing the same and uses of said nanospheres.

The present invention relates to a nanosphere comprising an equal numberof a human SEC14-like protein and a cognate ligand of said SEC14-likeprotein as well as to methods of producing the same and uses of saidnanospheres.

RELATED ART

The SEC14 gene product SEC14p was first identified in the yeastSaccharomyces cerevisiae, where it serves as transfer protein ofphosphatidylinositol from the Golgi apparatus to the plasma membrane.The X-ray structure of the domain in SEC14 proteins reveals acharacteristic alpha-beta-alpha sandwich with a hydrophobic pocket forlipid binding. Sec14p is essential for the biogenesis of secretoryvesicles from the trans-Golgi network by integrating lipid signallingevents with proteins involved in vesicle budding. Yeast homologs ofSEC14p (SFH2, SFH3, SFH4, and SFH5) fulfil complementary functions bymodulating PtdIns kinase and phospholipase D activities and by promotingphosphoinositide production (LLi, X., et al., Mol Biol Cell. 200011:1989-2005 and references cited therein).

In higher eukaryotes functional homologs of yeast SEC14p constitute theSEC14-like family of proteins with related functions (Peterman, T. K.,et al., Plant Physiol. 2004 136: 3080-3094). Protein sequence analysisand classification by the InterPro integrated database(https://www.ebi.ac.uk/interpro/) predicts that all members of theSEC14-like family of proteins have in common a characteristic CRAL-TRIO(IPR001251) domain derived from the primary structure of CRALBP and thetriple function TRIO protein. The CRAL-TRIO domain represents astructural scaffold for sequestering small lipophilic molecules(Panagabko C, et al., Biochemistry 2003 42:6467-6474 and referencescited therein). The domain may either constitute all of a SEC14-likeprotein or only part of it. CRAL-TRIO-only proteins like SEC14p, CRALBPor α-TTP have been identified as cytosolic factors for the intermembranetransfer of phosphatidylinositol, 11-cis-retinal and of α-tocopherol(α-tol) respectively (Panagabko C, et al., Biochemistry 200342:6467-6474 and references cited therein).

α-Tocopherol transfer protein (α-TTP) is a cytosolic 32 kDa protein thatfacilitates the transport of lipophilic vitamin E molecules throughhydrophilic media and to be assimilated by the organism. It belongs tothe SEC14-like protein family, known to be involved in lipid regulation(Panagabko C, et al., Biochemistry 2003 42:6467-6474; L. Aravind, etal., Curr. Biol. 1999 9:195-197 and references cited therein). The foldconsists of five parallel β-strands constituting the floor of thebinding cavity, a variable number of alpha-helices and a mobile helicalgate at the carboxy-terminal region that allows the lipophilic cognateligand to access the binding pocket (Stocker A. Ann N Y Acad Sci. 20041031:44-59; Meier R, et al., J Mol Biol 2003 331: 725-734). α-TTP hasbeen isolated in both rats and humans, and it is mainly expressed in theliver, but it is also present in the placenta and in the brain(Kaempf-Rotzoll, et al., Placenta 2003 24, 439-444 and references citedtherein). α-TTP plays a key role in the regulation of vitamin E inhepatocytes and is essential to the health of the organism, as its poorexpression or mutation is directly associated to occurrence of AVEDgenetic disease (Ouahchi K., et al., Nat. Genet. 1995 9:141-145).

In 1987, Cellular retinaldehyde-binding protein (CRALBP) was identifiedas high affinity binder with nanomolar affinities for 9-cis-retinal(K_(d)=53 nM), 11-cis-retinal (K_(d)=20 nM) and 11-cis-retinol (K_(d)=60nM) (Saari J C, and Bredberg D L., J Biol Chem. 1987 262:7618-22). Thesame study showed that CRALBP does not bind to either 13-cis orall-trans-retinal. An additional function of CRALBP is given by itscapability of protecting its cognate cis-cognate ligands from prematureisomerization. CRALBP also increases the retinal flux of the visualcycle, the eye's biochemical regeneration pathway from all-trans-retinalto 11-cis-retinal. In this pathway CRALB stimulates the isomeraseactivity of RPE65 (P. D. Kiser, et al., 2015 Nature Chemical Biology11:409-415) and facilitates binding of 11-cis-retinol into the RDH5dehydrogenase (Gamble M V1, et al., J Lipid Res. 1999 40:2279-92).Finally it chaperones translocation of 11-cis-retinal from RDH5 throughthe cytoplasm out of the cell by unknown mechanisms. Characterization ofgene mutations of human CRALBP could show that this protein is essentialfor efficient dark adaptation in rods and cones (M. S. Burstedt, et al.,2003 Vision Res. 43:2559-2571).

The SEC14-like Clavesins 1 and 2 are both expressed exclusively inneurons. These proteins are cytosolic but also bind to theendosome/lysosome compartment through their CRAL-TRIO domains byinteracting with phosphatidylinositol 3,5-bisphosphate abundant in theendosomal membrane (Katoh Y, et al., J Biol Chem. 2009 284:27646-54).Clavesins are enriched on clathrin coated vesicles where they form acomplex with clathrin heavy chain and adaptor protein-1, major coatcomponents of clathrin coated vesicles. Isoform-specific knockdown ofclavesins in neurons using lentiviral delivery of interfering RNAindicates a unique neuron-specific regulation of late endosome/lysosomemorphology (Katoh Y, et al., J Biol Chem. 2009 284:27646-54).

SEC14-like proteins such as α-TTP and CRALBP bind specific naturalcognate ligands with low nano-molar affinity. Such cognate ligands aresequestered from the plasma and selected to overcome the thermodynamicbarrier impairing free diffusion of insoluble lipids (Cohn, W., Am JClin Nutr 1999 69:156-157). CRALBP-mediated intracellular 11-cis-retinaltransfer in the eye is essential for persistent vision (M. S. Burstedt,et al., 2003 Vision Res. 43:2559-2571). α-TTP is essential for vitamin Ehomeostasis in man by selectively retaining α-tocopherol, the vitamin Eisomer with the highest antioxidant potency (Kono, N. and Arai, H.Traffic 2015 16: 19-34).

Numerous heritable diseases are linked to SEC14-like proteins. Defectsin the human α-TTP gene product of TTPA are reported to cause phenotypesof autosomal recessive ataxia with isolated vitamin E deficiency (AVED)(Ouahchi K., et al., Nat. Genet. 1995 9:141-145). The disease ischaracterized by undetectable or markedly reduced plasma levels ofvitamin E, spinocerebellar degeneration, ataxia, areflexia andproprioception loss. Another form of ataxia with related neurologicalphenotypes is caused by mutations in the SEC14-like Caytaxin geneproduct of ATCAY (Bomar J. M., et al., Nat. Genet. 2003 35:264-269).Defects in the CRALBP gene product of the RLBP1 gene lead to severeretinal pathologies (Maw M. A., et al., 1997 Nat. Genet. 17:198-200).

SUMMARY OF THE INVENTION

The present invention relates to the surprising finding of previouslyunknown nanospherical aggregates of SEC14-like family of proteins withtheir cognate ligands, the methods of production the same and the usesthereof.

Thus, in a first aspect the present invention provides for a nanospherecomprising, preferably consisting of, an equal number of (i) a humanSEC14-like protein, and (ii) a cognate ligand of said SEC14-likeprotein. Preferably, said equal number is of 3 to 60, furtherpreferably, said equal number is of 9 to 60. In a very preferredembodiment of the present invention, said human SEC14-like protein isselected from (a) α-tocopherol transfer protein (α-TTP); (b) Cellularretinaldehyde binding protein (CRALBP); (c) Clavesin1 (CLVS1); (d)Clavesin2 (CLVS2); and (e) alpha-tocopherol transfer protein like(TTPAL).

In further aspects, the present invention provides for methods ofproducing the inventive nanospheres and uses of the inventivenanospheres.

Thus, in a further aspect, the present invention provides for a methodof producing a nanosphere comprising, preferably consisting of, an equalnumber of (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein, wherein said method comprises the steps of (a)providing said SEC14-like protein in an aqueous solution I, wherein theconcentration of said SEC14-like protein in said solution I is 1 μM to 5mM, and wherein the pH of said solution I is 6 to 9, and whereinpreferably said solution I comprises a salt, wherein the concentrationof said salt is 10 mM to 500 mM; (b) providing said cognate ligand ofSEC14-like protein in a solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM, and wherein the solvent of said solution II is a water solublesolvent; (c) generating a solution III by combining said solution I andsaid solution II, wherein the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 4:1 to 1:4(molar/molar), and wherein the volume of said water soluble solvent insaid solution III is of between 0.5-8% (vol/vol); (d) allowing saidSEC14-like protein and said cognate ligand of said SEC14-like protein toassemble into a nanosphere; (e) separating said nanosphere from saidsolution III; (f) optionally purifying said nanosphere.

In again a further aspect, the present invention provides for a methodof producing a nanosphere comprising, preferably consisting of, an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein; wherein said method comprises the steps of (a)providing said SEC14-like protein in an aqueous solution I, wherein theconcentration of said SEC14-like protein in said solution I is 1 μM to 5mM, and wherein the pH of said solution I is 6 to 9; (b) providing saidcognate ligand of SEC14-like protein in an aqueous solution II, whereinthe concentration of said cognate ligand of SEC14-like protein in saidsolution I is 5 μM to 500 mM; and wherein said solution II comprises adetergent; (c) generating a solution III by combining said solution Iand said solution II, wherein the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 4:1 to 1:4(molar/molar); (d) removing said detergent from said solution III,wherein removing said detergent from said solution III allows saidSEC14-like protein and said cognate ligand of said SEC14-like protein toassemble into a nanosphere; (e) separating said nanosphere from saidsolution III; (f) optionally purifying said nanosphere.

In again a further aspect, the present invention provides for a methodof producing a nanosphere comprising, preferably consisting of, an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein; wherein said method comprises the steps of (a)providing said SEC14-like protein in an aqueous solution I, wherein theconcentration of said SEC14-like protein in said solution I is 1 μM to 5mM, and wherein the pH of said solution I is 6 to 9, and whereinpreferably said solution I comprises a salt, wherein the concentrationof said salt is 10 mM to 500 mM; (b) providing said cognate ligand ofSEC14-like protein in a solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM, and wherein the solvent of said solution II is a water solublesolvent; (c) generating a solution III by combining said solution I andsaid solution II, wherein the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 4:1 to 1:4(molar/molar), and wherein the volume of said water soluble solvent insaid solution III is of between 0.5-8% (vol/vol); (d) allowing saidSEC14-like protein and said cognate ligand of said SEC14-like protein toform monomeric complexes consisting of one of said SEC14-like proteinand one of said cognate ligand of said SEC14-like protein; (e)separating said monomeric complexes from said solution III; (f)optionally purifying said monomeric complexes; (g) generating an aqueoussolution IV, wherein said solution IV comprises said monomericcomplexes, and wherein the concentration of said monomeric complex insaid solution IV is 5 mg/ml to 50 mg/ml; and wherein the pH of saidsolution IV is 6 to 9, and wherein preferably said solution IV comprisesa salt, wherein the concentration of said salt is 10 mM to 500 mM; (h)allowing said monomeric complexes to form crystals of said nanosphere.

In again a further aspect, the present invention provides for a methodof producing a nanosphere comprising, preferably consisting of, an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein; wherein said method comprises the steps of (a)providing said SEC14-like protein in an aqueous solution I, wherein theconcentration of said SEC14-like protein in said solution I is 1 μM to 5mM, and wherein the pH of said solution I is 6 to 9; (b) providing saidcognate ligand of SEC14-like protein in an aqueous solution II, whereinthe concentration of said cognate ligand of SEC14-like protein in saidsolution I is 5 μM to 500 mM; and wherein said solution II comprises adetergent; (c) generating a solution III by combining said solution Iand said solution II, wherein the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 4:1 to 1:4(molar/molar); (d) removing said detergent from said solution III,wherein removing said detergent from said solution III allows saidSEC14-like protein and said cognate ligand of said SEC14-like protein toform monomeric complexes consisting of one of said SEC14-like proteinand one of said cognate ligand of said SEC14-like protein; (e)separating said monomeric complexes from said solution III; (f)optionally purifying said monomeric complexes; (g) generating an aqueoussolution IV, wherein said solution IV comprises said monomericcomplexes, and wherein the concentration of said monomeric complex insaid solution IV is 5 mg/ml to 50 mg/ml, and wherein the pH of saidsolution IV is 6 to 9, and wherein preferably said solution IV comprisesa salt, and wherein the concentration of said salt is 10 mM to 500 mM;(h) allowing said monomeric complexes to form crystals of saidnanosphere.

In again a further aspect, the present invention provides for apharmaceutical composition comprising (a) the nanosphere of the presentinvention; and (b) a pharmaceutically acceptable carrier.

In again a further aspect, the present invention provides for thenanosphere or the pharmaceutical composition of the present inventionfor use in a method of the treatment or prevention, preferably of thetreatment, of Ataxia with Vitamin E Deficiency (AVED), muscle dystrophy,hypolipidemia, hypolipoproteinemia, dyslipidemia, human infertility,impaired wound healing or an inflammatory disease, wherein preferablysaid inflammatory disease is arthritis.

Further aspects and preferred embodiments of the present invention willbecome apparent as this description proceeds.

DESCRIPTION OF FIGURES

FIG. 1A Preparative SEC trace of a mixture of cognate ligand-complexescomposed of monomeric α-TTP-α-Tol and of α-TTP-α-Tol nanospherescomprising α-TTP trimers. Peak S represents α-TTP-α-Tol nanospherescentering at a retention volume that correlates to a mass of 0.76 Mdaand peak M represents monomeric α-TTP-α-Tol that correlates to a mass of32 kDa. Peak V contains highly aggregated protein that centers at thecolumn's void volume. FIG. 1B Analytial SEC traces of apo-α-TTP (blacktrace) and of holo-α-TTP representing a mixture of cognateligand-complexes composed of monomeric α-TTP-α-Tol and of α-TTP-α-Tolnanospheres comprising α-TTP trimers (grey trace). The black trace ofapo-α-TTP indicates the presence of dimeric apo-α-TTP centering at aretention volume that correlates to a mass of 64 kDa and of monomericapo-α-TTP centering at a retention volume that correlates to a mass of32 kDa. The grey holo-α-TTP trace indicates the presence of α-TTP-α-Tolnanospheres centering at a retention volume that correlates to a mass of0.76 Mda and of monomeric α-TTP-α-Tol that correlates to a mass of 32kDa. A minor peak D is visible most probably consisting of cognateligand free dimeric apo-α-TTP that centers at a retention volume thatcorrelates to a mass of 64 kDa.

FIG. 2: Negative-stain transmission electron microscopy (TEM) images ofthe peak fraction of peak S from the preparative SEC revealed thephysical presence of spherical objects.

FIG. 3: Western blot of peak fractions from preparative SEC; thepresence of recombinant α-TTP was confirmed by anti-6×His and byanti-α-TTP antibodies.

FIG. 4: Native polyacrylamide gel electrophoresis of peak fractions M, Dand S from preparative SEC: Peak S contains oligomeric α-TTP-α-Tolnanospheres with an approximate mass of 0.80 MDa, peak D contains mostlyhomo-dimeric apo-α-TTP with an approximate mass of 64 kDa and peak Mcontains mostly monomeric α-TTP-α-Tol.

FIG. 5: Thermal denaturation traces monitored by CD spectroscopy at 222nm for monomeric apo-α-TTP (1), monomeric α-TTP-α-Tol (2) and oligomericα-TTP-α-Tol nanospheres (3).

FIG. 6: Atomic model of the tetracosameric assembly of oligomericα-TTP-α-Tol nanosphere: On the left are depicted views of the atomicmodel along the three symmetry axes. The inset depicts cystine bondformation between two adjacent C80 across the rhombohedral channel alongthe two-fold symmetry axis in the oxidized form of the α-TTP-α-Tolnanosphere. On the right is shown a geometric representation of thetwisted cantellated cube (TCC) with a ribbon cartoon of a monomersitting on a node.

FIG. 7A Schematic view of protein-protein interactions on the three-foldaxis (A) and summary of protein-protein interactions contributing to thestability of α-TTP-α-Tol nanospheres FIG. 7B The FoldX (Guerois R,Nielsen J E, Serrano L (2002), J Mol Bio 320:369-387) computer algorithmwas used to evaluate protein-protein interactions. For this theα-TTP-α-Tol nanosphere was minimized (at 298K, pH 7, 0.05M ionicstrength) in order to generate a reference structure for subsequentenergy calculations and structure comparisons.

FIG. 8A Mostly hydrophobic residues are clustered in a characteristicsequence pattern leading to the trimeric forms in α-TTP-α-Tolnanospheres. A highly similar pattern of hydrophobic residues is presentin the primary sequence of CRALBP (SEQ ID NO:8 and SEQ ID NO:9). FIG. 8BPrimary sequence alignment of the N-terminal segment of α-TTP (aa's47-90) and related segments in other SEC14-like proteins using theMULTALIN webservice (Corpet, F.; Nucleic Acids Res. 198816:10881-10890). Conserved or semi-conserved residues are depicted inlight gray. The mostly hydrophobic residues of the characteristicsequence pattern are marked by filled triangles (SEQ ID NO:10, SEQ IDNO:11, SEQ ID NO:12 SEQ ID NO:13 and SEQ ID NO:14). FIG. 8C PSIPREDbased comparison of the secondary helix-loop-helix structures of α-TTP(aa's 47-90) and of CRALBP (aa's 91-123) reveal high structuralsimilarity (SEQ ID NO:15 and SEQ ID NO:16).

FIG. 9: Depicted are the primary sequences of preferred SEC14-likeproteins with the residues of the characteristic sequence patterns beinghighlighted in light gray.

FIG. 10: Negative-stain transmission electron microscopy (TEM) images ofthe peak fraction of CRALBP-11-cis-retinal nanospheres from theanalytical SEC revealed the physical presence of spherical objects in asize range between 9 and 48 nm.

FIG. 11A-11C: Analytical SEC traces of mixtures of cognateligand-complexes composed of monomeric CRALBP-9-cis-retinal and ofCRALBP-9-cis-retinal nanospheres. FIG. 11A The peak at a retentionvolume of 17.5 ml correlates to an average mass of 36 kDa and the peakat 15 ml correlates to an average mass of 420 kDa; FIG. 11B Mixture withthe ligand previously added in the presence of sodium cholate: The peakat a retention volume of 17.8 ml correlates to an average mass of 36 kDaand the peak at 13.5 ml correlates to an average mass of 1700 kDa; FIG.11C Mixture with the ligand previously added in the presence of ethanol:The peak at a retention volume of 17.8 ml correlates to an average massof 36 kDa and the peak at 15 ml correlates to an average mass of 540kDa. The solid traces represent the protein concentration monitored at280 nm while the dashed traces represent the concentration of bound9-cis-retinal monitored at 405 nm. Arrows with numbers indicate themultiplicity of the homo oligomeric complexes.

FIG. 12A-12B: Transcytosis of monomeric α-TTP-α-Tol and of α-TTP-α-Tolnanospheres comprising α-TTP trimers FIG. 12A Simultaneous determinationof rates of transcytosis (hatched area) and of paracellular flux (darkarea) across a human umbelical vein endothelial cell (HUVEC) monolayer.FIG. 12B Corresponding rates of transcytosis and paracellular fluxacross a heterogeneous human epithelial colorectal adenocarcinoma cell(CaCo-2) monolayer.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs.

Nanosphere: The term “nanosphere”, as used herein, refers to acomposition, typically and preferably a polyhedral structure, formed bya number of a SEC14-like protein and an equally number of the cognateligand of said SEC14-like protein. Typically and preferably, said numberis at least 3 and at most 60. Further preferably, said number is atleast 9 and at most 60. Again further preferably, said equal number ofsaid SEC14-like protein and the cognate ligand of said SEC14-likeprotein is a multiple of 3, and wherein further preferably said equalnumber is 3, 9, 12, 24, 36, 48 and 60, again further preferably 9, 12,24, 36, 48 and 60. Again further preferably, said equal number of saidSEC14-like protein and the cognate ligand of said SEC14-like protein isa multiple of 3, and said number is at least 3 and at most 60, whereinfurther preferably said equal number is 3, 9, 12, 24, 36, 48 and 60,again further preferably 9, 12, 24, 36, 48 and 60. Typically andpreferably, said polyhedral structure is of a size of between 5 nm and60 nm, preferably of a size of between 7 nm and 55 nm, and furtherpreferably of a size of between 9 nm and 48 nm as determined, preferablyby dynamic light scattering in a manner as described in present Example3E. Thus, typically and preferably the term “nanosphere”, as usedherein, refers to a polyhedral structure of a size of between 5 nm and60 nm, preferably of a size of between 7 nm and 55 nm, and furtherpreferably of a size of between 9 nm and 48 nm, as preferably determinedby dynamic light scattering, and further preferably as described inpresent Example 3E, and wherein said polyhedral structure is formed byat least three, further preferably said polyhedral structure is formedby at least nine, further preferably by at least twelve or again furtherpreferably by at least 24, 36, 48 or 60 copies of a SEC14-like proteinand an equal number of the cognate ligand of said SEC14-like protein.Typically and preferably, said regular number of equal SEC14-likeproteins form a hollow protein coat with said polyhedral structure of asize of between 5 nm and 60 nm, preferably of a size of between 7 nm and55 nm, and further preferably of a size of between 9 nm and 48 nm, aspreferably determined by dynamic light scattering, and furtherpreferably as described in present Example 3E, and in which polyhedralstructure the equal number of the cognate ligand of said SEC14-likeprotein is aggregated. Thus, the stoichiometry in said nanosphere ofsaid SEC14-like protein and the cognate ligand of said SEC14-likeprotein is 1:1. Typically and preferably, said nanospheres are composedof one type of SEC14-like protein and an equal number of the cognateligand of said SEC14-like protein. Typically and preferably, the equalSEC14-like protein building blocks forming said hollow coat with saidpolyhedral structure are also termed herein “protomers”.

SEC14-like protein: The term “SEC14-like protein” or “SEC14-like familyof protein”, as interchangeably as used herein, refers to a proteinstructural domain (Sha B1, et al., Nature. 1998 391:506-10) designatedCRAL-TRIO that binds, typically and preferably small lipophilic,molecules (Panagabko C, et al., Biochemistry 2003 42:6467-6474). TheCRAL-TRIO lipid-binding domain is a a/(3 domain, which forms a largehydrophobic pocket. Its pocket floor is constituted by six β-strandswith strands 2, 3, 4 and 5 constituting a parallel beta sheet and withstrands 1 and 6 being anti-parallel. The sides of the cavity are formedby α-helices. The CRAL-TRIO domain may either constitute all of theprotein or only part of it (Sha B1, et al., Nature. 1998 391:506-10;Panagabko C, et al., Biochemistry 2003 42:6467-6474). Typically andpreferably, the cognate ligand free form of the SEC14-like protein isalso termed herein as the “apo” form of said SEC14-like protein.

A cognate ligand of a SEC14-like protein: The term “a cognate ligand ofa SEC14-like protein”, as used herein, refers to a molecule, typicallyand preferably to a lipid, that binds to a CRAL-TRIO lipid bindingpocket with at least nanomolar affinity of typically and preferably1-100 nM, further typically and preferably with an affinity of 6-60 nM,and which molecule is typically and preferably functionally associatedwith the SEC14-like protein. Functionally associated: The term“functionally associated”, as used herein, refers to the physiologicalfunction of the SEC14-like protein that critically depends on thebinding of the physiological cognate ligand, termed herein cognateligand, with at least nanomolar affinity of typically and preferably1-100 nM, further typically and preferably with an affinity of 6-60 nM.By way of example, R,R,R-α-tocopherol represents a cognate ligand ofα-tocopherol transfer protein (α-TTP) and R,R,R-α-tocopherol representsone of the most powerful fat-soluble antioxidants.

Bound: The term “bound”, as used herein, refers to all possible ways,preferably chemical interactions, by which two molecules are joinedtogether. Chemical interactions include covalent and non-covalentinteractions. Typical examples for non-covalent interactions are ionicinteractions, hydrophobic interactions or hydrogen bonds, whereascovalent interactions are based on covalent bonds. In preferredembodiments, each of said SEC14-like protein is bound to one of said atleast one cognate ligand of said SEC14-like protein by way of at leastone covalent or at least one non-covalent interaction. Furtherpreferably, each of said SEC14-like protein is bound to one of said atleast one cognate ligand of said SEC14-like protein by way of at leastone non-covalent interaction.

Sequence identity: The sequence identity of two given amino acidsequences is determined based on an alignment of both sequences.Algorithms for the determination of sequence identity are available tothe artisan. Preferably, the sequence identity of two amino acidsequences is determined using publicly available computer homologyprograms such as the “BLAST” program(http://blast.ncbi.nlm.nih.gov/Blast.cgi) or the “CLUSTALW”(http://www.genome.jp/tools/clustalw/), and hereby preferably by the“BLAST” program provided on the NCBI homepage athttp://blast.ncbi.nlm.nih.gov/Blast.cgi, using the default settingsprovided therein. Typical and preferred standard settings are: expectthreshold: 10; word size: 3; max matches in a query range: 0; matrix:BLOSUM62; gap costs: existence 11, extension 1; compositionaladjustments: conditional compositional score matrix adjustment.

Position corresponding to residues . . . : The position on an amino acidsequence, which is corresponding to given residues of another amino acidsequence can be identified by sequence alignment, typically andpreferably by using the BLASTP algorithm, most preferably using thestandard settings. Typical and preferred standard settings are: expectthreshold: 10; word size: 3; max matches in a query range: 0; matrix:BLOSUM62; gap costs: existence 11, extension 1; compositionaladjustments: conditional compositional score matrix adjustment. A verypreferred determination of the “position corresponding to residues . . .” is outlined in FIG. 8A and FIG. 8B by way of the SEC14-like proteinsα-TTP and CRALBP which corresponds a preferred embodiment of the presentinvention.

Effective amount: The term “effective amount”, as used herein, refers toan amount necessary or sufficient to realize a desired biologic effect.Preferably, the term “effective amount” refers to an amount of ananosphere of the present invention that (i) treats or prevents theparticular disease, medical condition, or disorder, (ii) attenuates,ameliorates, or eliminates one or more symptoms of the particulardisease, medical condition, or disorder, or (iii) prevents or delays theonset of one or more symptoms of the particular disease, medicalcondition, or disorder described herein. An effective amount of theinventive nanosphere or said pharmaceutical composition, would be theamount that achieves this selected result, and such an amount could bedetermined as a matter of routine by a person skilled in the art. Theeffective amount can vary depending on the particular composition beingadministered and the size of the subject. One of ordinary skill in theart can empirically determine the effective amount of a particularcomposition of the present invention without necessitating undueexperimentation.

The present invention relates to the surprising finding of previouslyunknown nanospherical aggregates of SEC14-like family of proteins withtheir cognate ligands, the methods of production the same and the usesthereof.

Thus, in a first aspect the present invention provides for a nanospherecomprising, preferably consisting of, an equal number of (i) a humanSEC14-like protein, and (ii) a cognate ligand of said SEC14-likeprotein. Preferably, said equal number is of 3 to 60. Furtherpreferably, said equal number is of 9 to 60.

In a very preferred embodiment of the present invention, said equalnumber is a multiple of 3. In a further very preferred embodiment of thepresent invention, said equal number is a multiple of 3, and said equalnumber is of 3 to 60. Thus, in a further very preferred embodiment ofthe present invention, said equal number is a multiple of 3, and saidequal number is of 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42,45, 48, 51, 54, 57 or 60.

In a very preferred embodiment of the present invention, said equalnumber is 3, 9, 12, 24, 36, 48 or 60. In a further very preferredembodiment of the present invention, said equal number is 9, 12, 24, 36,48 or 60. In a further very preferred embodiment of the presentinvention, said equal number is 24 or 48.

In an again very preferred embodiment of the present invention, saidhuman SEC14-like protein is selected from (a) α-tocopherol transferprotein (α-TTP); (b) Cellular retinaldehyde binding protein (CRALBP);(c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2); and (e) alpha-tocopheroltransfer protein like (TTPAL).

In an again very preferred embodiment of the present invention, saidSEC14-like protein is α-tocopherol transfer protein (α-TTP), whereinpreferably said equal number is 24. Preferably said cognate ligand ofsaid α-tocopherol transfer protein (α-TTP) is a tocopherol, whereinpreferably said tocopherol is α-tocopherol and wherein furtherpreferably said α-tocopherol is R,R,R-α-tocopherol.

In an again very preferred embodiment of the present invention, saidSEC14-like protein is α-tocopherol transfer protein (α-TTP) and saidcognate ligand of said α-tocopherol transfer protein (α-TTP) isα-tocopherol, and wherein said equal number is of 3 to 60, and whereinpreferably said α-tocopherol is R,R,R-α-tocopherol.

In an again very preferred embodiment of the present invention, saidSEC14-like protein is α-tocopherol transfer protein (α-TTP) and saidcognate ligand of said α-tocopherol transfer protein (α-TTP) isα-tocopherol, and wherein said equal number is of 9 to 60, and whereinpreferably said α-tocopherol is R,R,R-α-tocopherol.

In an again very preferred embodiment of the present invention, saidSEC14-like protein is α-tocopherol transfer protein (α-TTP) and saidcognate ligand of said α-tocopherol transfer protein (α-TTP) isR,R,R-α-tocopherol, and said equal number is of 3 to 60, whereinpreferably said equal number is 3, 9, 12, 24, 36, 48 or 60. In a furthervery preferred embodiment of the present invention, said equal number is24 or 48.

In an again very preferred embodiment of the present invention, saidSEC14-like protein is α-tocopherol transfer protein (α-TTP) and saidcognate ligand of said α-tocopherol transfer protein (α-TTP) isR,R,R-α-tocopherol, and said equal number is of 9 to 60, whereinpreferably said equal number is 9, 12, 24, 36, 48 or 60. In a furthervery preferred embodiment of the present invention, said equal number is24 or 48.

In an again very preferred embodiment, the present invention providesfor a nanosphere comprising, preferably consisting of, an equal numberof (i) a human SEC14-like protein, and (ii) a cognate ligand of saidSEC14-like protein, wherein said equal number is a multiple of 3, andwherein preferably said number is of 3 to 60, and wherein said humanSEC14-like protein is selected from (a) α-tocopherol transfer protein(α-TTP); (b) Cellular retinaldehyde binding protein (CRALBP); (c)Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2); and (e) alpha-tocopheroltransfer protein like (TTPAL).

In an again very preferred embodiment of the present invention, saidSEC14-like protein is Cellular retinaldehyde binding protein (CRALBP).Preferably said cognate ligand of said CRALBP is a cis-retinol or a cisretinal, wherein further preferably said cis-retinol or said cis retinalis selected from 9-cis-retinal, 11-cis-retinal, 9,13-dicis-retinal,9-cis-retinol, 11-cis-retinol and 9,13-dicis-retinol. In a verypreferred embodiment of the present invention, said cognate ligand ofsaid CRALBP is 9-cis-retinal. In a further very preferred embodiment ofthe present invention, said cognate ligand of said CRALBP is11-cis-retinal. In another preferred embodiment of the presentinvention, said cognate ligand of said CRALBP is 9-cis-retinol. In againanother preferred embodiment of the present invention, said cognateligand of said CRALBP is 11-cis-retinol. In again another embodiment ofthe present invention, said cognate ligand of said CRALBP is9,13-dicis-retinal. In again another embodiment of the presentinvention, said cognate ligand of said CRALBP is 9,13-dicis-retinol. Ina preferred embodiment of the present invention, said SEC14-like proteinis a protein comprising an amino acid sequence selected from (a) SEQ IDNO:3 (α-TTP HUMAN); (b) SEQ ID NO:4 (CRALBP HUMAN); (c) SEQ ID NO:5(CLVS1 HUMAN); (d) SEQ ID NO:6 (CLVS2 HUMAN); and (e) SEQ ID NO:7 (TTPALHUMAN).

In another preferred embodiment of the present invention, saidSEC14-like protein comprises an amino acid sequence stretch, whereinsaid amino acid sequence stretch has the amino acid sequence selectedfrom (a) amino acids 56 to 74 of SEQ ID NO:3; (b) amino acids 100 to 118of SEQ ID NO:4; (c) amino acids 80 to 98 SEQ ID NO:5; (d) amino acids 58to 76 SEQ ID NO:6; and (e) amino acids 85 to 103 SEQ ID NO:7.

In a further preferred embodiment of the present invention, the aminoacid sequence of said SEC14-like protein comprises (a) an amino acidresidue selected from L and I on the position of said amino acidsequence of said SEC14-like protein which corresponds to the position 56of SEQ ID NO:3; (b) the amino acid residue F on the position of saidamino acid sequence of said SEC14-like protein which corresponds to theposition 61 of SEQ ID NO:3; (c) an amino acid residue selected from L,V, Q, H and Y on the position of said amino acid sequence of saidSEC14-like protein which corresponds to the position 63 of SEQ ID NO:3;(d) an amino acid residue selected from W, Y, F and L on the position ofsaid amino acid sequence of said SEC14-like protein which corresponds tothe position 67 of SEQ ID NO:3; (e) the amino acid residue L on theposition of said amino acid sequence of said SEC14-like protein whichcorresponds to the position 70 of SEQ ID NO:3; or (f) an amino acidresidue selected from Y, V, F and H on the position of said amino acidsequence of said SEC14-like protein which corresponds to the position 74of SEQ ID NO:3; wherein said amino acid sequence of said SEC14-likeprotein comprises at least two, preferably at least three, furtherpreferably at least four, again further preferably at least five of anyone of said amino acid residues of (a)-(f); and wherein preferably atleast four amino acid residues of any one of (a)-(f) of said amino acidsequence of a first of said number of SEC14-like protein comprised bysaid nanosphere is bound to at least four amino acid residues of any oneof (a)-(f) of said amino acid sequence of a second and of a third ofsaid number of SEC14-like protein comprised by said nanosphere.

In a further preferred embodiment of the present invention, saidSEC14-like protein comprises an amino acid sequence, wherein said aminoacid sequence of said SEC14-like protein comprises (a) an amino acidresidue selected from L and I on the position which corresponds to theposition 56 of SEQ ID NO:3; (b) the amino acid residue F on the positionwhich corresponds to the position 61 of SEQ ID NO:3; (c) an amino acidresidue selected from L, V, Q, H and Y on the position which correspondsto the position 63 of SEQ ID NO:3; (d) an amino acid residue selectedfrom W, Y, F and L on the position which corresponds to the position 67of SEQ ID NO:3; (e) the amino acid residue L on the position whichcorresponds to the position 70 of SEQ ID NO:3; or (f) an amino acidresidue selected from Y, V, F and H on the position which corresponds tothe position 74 of SEQ ID NO:3; wherein said amino acid sequence of saidSEC14-like protein comprises at least two, preferably at least three,further preferably at least four, again further preferably at least fiveof any one of said amino acid residues of (a)-(f); and whereinpreferably at least four amino acid residues of any one of (a)-(f) ofsaid amino acid sequence of a first of said number of SEC14-like proteincomprised by said nanosphere is bound to at least four amino acidresidues of any one of (a)-(f) of said amino acid sequence of a secondand of a third of said number of SEC14-like protein comprised by saidnanosphere.

Without being bound by this theory, it is believed that theaforementioned amino sequence residues and patterns favor the formationof trimeric aggregates of said SEC14-like protein, which in turn favorthe formation of the inventive nanospheres. Moreover, and again withoutbeing bound by this theory, it is believed that the process ofsequestration of the cognate ligand of said SEC14-like protein isaccompanied by conformational rearrangements in the SEC14-like proteinincluding a closing movement of a helical element of its C-terminalregion designated mobile gate. Thus, it is believed, without being boundby this theory, that the formation of trimeric aggregates and inparticular the inventive nanospheres depend on conformationalrearrangements within the N-terminal region of the SEC14-like proteinthat effect the unmasking of the helix-turn-helix segment that carriesthe aforementioned amino sequence residues and patterns otherwiseinaccessible to solvent. Typically, the loading procedure of saidcognate ligand of said SEC14-like protein yields mixtures of monomericand nanospheric protein-ligand complexes that can be both purified bysuitable chromatrographic methods such as size exclusion chromatographyand/or anionic exchange chromatography.

Furthermore, we have shown that the inventive nanospheres, in particularthe inventive nanospheres of the SEC14-like protein alpha-TTP doefficiently transcytose through primary human umbilical vein endothelialcells. This process was shown to be highly specific by demonstrating theabsence of transcytosis of the same nanospheres through a standardepithelial cell line. As a consequence, the inventive nanospheres areexpected to be highly suitable to overcome the blood brain barrier wheninjected into the blood stream.

In a preferred embodiment of the present invention, each of said cognateligand of said SEC14-like protein is bound to one of said SEC14-likeprotein by way of at least one non-covalent interaction, whereinpreferably each of said cognate ligand of said SEC14-like protein isbound to only one of said SEC14-like protein by way of at least onenon-covalent interaction.

In a further aspect, the present invention provides for a method ofproducing a nanosphere comprising, preferably consisting of, an equalnumber of (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein, wherein preferably said equal number is 3 to60, wherein said method comprises the steps of (a) providing saidSEC14-like protein in an aqueous solution I, wherein the concentrationof said SEC14-like protein in said solution I is 1 μM to 5 mM, andwherein the pH of said solution I is 6 to 9, and wherein preferably saidsolution I comprises a salt, wherein the concentration of said salt is10 mM to 500 mM; (b) providing said cognate ligand of SEC14-like proteinin a solution II, wherein the concentration of said cognate ligand ofSEC14-like protein in said solution I is 5 μM to 500 mM, and wherein thesolvent of said solution II is a water soluble solvent; (c) generating asolution III by combining said solution I and said solution II, whereinthe ratio of the concentration of said SEC14-like protein and theconcentration of said cognate ligand of said SEC14-like protein in saidsolution III is of between 4:1 to 1:4 (molar/molar), and wherein thevolume of said water soluble solvent in said solution III is of between0.5-8% (vol/vol); (d) allowing said SEC14-like protein and said cognateligand of said SEC14-like protein to assemble into a nanosphere; (e)separating said nanosphere from said solution III; (0 optionallypurifying said nanosphere.

Further preferred embodiment of the inventive methods include thepreferred and very preferred embodiments of the inventive nanosphere. Inparticular, in a very preferred embodiment, said equal number is amultiple of 3, and wherein preferably said number is of 3 to 60, andwherein said human SEC14-like protein is selected from (a) α-tocopheroltransfer protein (α-TTP); (b) Cellular retinaldehyde binding protein(CRALBP); (c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2); and (e)alpha-tocopherol transfer protein like (TTPAL).

In a further aspect, the present invention provides for a method ofproducing a nanosphere comprising, preferably consisting of, an equalnumber of (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein, wherein preferably said equal number is 9 to60, wherein said method comprises the steps of (a) providing saidSEC14-like protein in an aqueous solution I, wherein the concentrationof said SEC14-like protein in said solution I is 1 μM to 5 mM, andwherein the pH of said solution I is 6 to 9, and wherein preferably saidsolution I comprises a salt, wherein the concentration of said salt is10 mM to 500 mM; (b) providing said cognate ligand of SEC14-like proteinin a solution II, wherein the concentration of said cognate ligand ofSEC14-like protein in said solution I is 5 μM to 500 mM, and wherein thesolvent of said solution II is a water soluble solvent; (c) generating asolution III by combining said solution I and said solution II, whereinthe ratio of the concentration of said SEC14-like protein and theconcentration of said cognate ligand of said SEC14-like protein in saidsolution III is of between 4:1 to 1:4 (molar/molar), and wherein thevolume of said water soluble solvent in said solution III is of between0.5-8% (vol/vol); (d) allowing said SEC14-like protein and said cognateligand of said SEC14-like protein to assemble into a nanosphere; (e)separating said nanosphere from said solution III; (f) optionallypurifying said nanosphere.

Further preferred embodiment of the inventive methods include thepreferred and very preferred embodiments of the inventive nanosphere. Inparticular, in a very preferred embodiment, said equal number is amultiple of 3, and wherein preferably said number is of 3 to 60, andwherein said human SEC14-like protein is selected from (a) α-tocopheroltransfer protein (α-TTP); (b) Cellular retinaldehyde binding protein(CRALBP); (c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2); and (e)alpha-tocopherol transfer protein like (TTPAL).

In a further preferred embodiment, the concentration of said SEC14-likeprotein in said solution I is 0.1 mM to 1 mM, and further preferably theconcentration of said SEC14-like protein in said solution I is 0.25 mMto 0.75 mM.

In a further preferred embodiment, the pH of said solution I is 7 to 8.Preferably said solution I comprises a salt, wherein the concentrationof said salt is 10 mM to 500 mM. Further preferred, the concentration ofsaid salt is 30 mM to 350 mM, and further preferably the concentrationof said salt is 100 mM to 250 mM.

In a further preferred embodiment, said salt is selected from a mono-,di-, tri- or tetravalent inorganic or organic salt, and wherein furtherpreferably said salt is selected from a di-, tri- or tetravalentinorganic or organic salt, and wherein again further preferably saidsalt comprises a divalent, tri, or tetravalent anion selected from HPO₄²⁻, SO₄ ²⁻, tartrate, malonate, D-myo-inositol 1,4,5-triphosphate andD-myo-inositol 1,3,4,5-tetrakis(phosphate) potassium salt.

In a further preferred embodiment, said concentration of said cognateligand of SEC14-like protein in said solution I is 30 μM to 300 mM,further preferably the concentration of said cognate ligand ofSEC14-like protein in said solution I is 200 μM to 200 mM.

The solvent of said solution II is a water soluble solvent. It is withinthe scope of the present invention that the water soluble solvent usedfor solution II may comprise minor amounts, i.e. up to 10% (v/v) ofwater even though typically and preferably said water soluble solventdoes not comprise any additional amounts of water other than the minoramount of water typically comprised in said water soluble solvent whensupplied by the manufacturer. Further preferably, said water solublesolvent dose not comprise more than 8% (v/v), preferably more than 7%(v/v), further preferably more than 5% (v/v) of water.

In a preferred embodiment of the present invention, said water solublesolvent is selected from methanol, ethanol, isopropanol, propanol,butanol, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), dioxan,methylpentane diol and glycerol; further preferably said water solublesolvent is selected from ethanol, isopropanol and dimethyl sulfoxide(DMSO).

In a preferred embodiment of the present invention, said ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 3:1 to 1:3 (molar/molar), and preferably the ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 2:1 to 1:2 (molar/molar).

In another preferred embodiment of the present invention, said volume ofsaid water soluble solvent in said solution III is of between 1-5%(vol/vol), and preferably the volume of said water soluble solvent insaid solution III is of between 2-4% (vol/vol).

In a preferred embodiment of the present invention, said allowing saidSEC14-like protein and said cognate ligand of said SEC14-like protein toassemble into a nanosphere is effected by keeping said solution III at atemperature of 4-37° C., preferably at room temperature, for a period of1 h to 24 h, preferably for a period of 12 to 24 h.

In a further preferred embodiment of the present invention, saidseparating said nanosphere from said solution III is effected by sizeexclusion chromatography or anionic exchange chromatography, preferablyby size exclusion chromatography.

In another preferred embodiment of the present invention, said purifyingsaid nanosphere is effected by size exclusion chromatography or anionicexchange chromatography, preferably by size exclusion chromatography.

In a further aspect, the present invention provides for a method ofproducing the inventive nanosphere as described herein, wherein saidnanosphere comprises, preferably consists of, an equal number of (i) ahuman SEC14-like protein, and (ii) a cognate ligand of said SEC14-likeprotein, wherein preferably said equal number is 3 to 60, wherein saidmethod comprises the steps of (a) providing said SEC14-like protein inan aqueous solution I, wherein the concentration of said SEC14-likeprotein in said solution I is 1 μM to 5 mM, and wherein the pH of saidsolution I is 6 to 9; (b) providing said cognate ligand of SEC14-likeprotein in an aqueous solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM; and wherein said solution II comprises a detergent; (c) generating asolution III by combining said solution I and said solution II, whereinthe ratio of the concentration of said SEC14-like protein and theconcentration of said cognate ligand of said SEC14-like protein in saidsolution III is of between 4:1 to 1:4 (molar/molar); (d) removing saiddetergent from said solution III, wherein removing said detergent fromsaid solution III allows said SEC14-like protein and said cognate ligandof said SEC14-like protein to assemble into a nanosphere; (e) separatingsaid nanosphere from said solution III; (f) optionally purifying saidnanosphere. Further preferred embodiment of the inventive methodsinclude the preferred and very preferred embodiments of the inventivenanosphere. In particular, in a very preferred embodiment, said equalnumber is a multiple of 3, and wherein preferably said number is of 3 to60, and wherein said human SEC14-like protein is selected from (a)α-tocopherol transfer protein (α-TTP); (b) Cellular retinaldehydebinding protein (CRALBP); (c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2);and (e) alpha-tocopherol transfer protein like (TTPAL).

In a further aspect, the present invention provides for a method ofproducing the inventive nanosphere as described herein, wherein saidnanosphere comprises, preferably consists of, an equal number of (i) ahuman SEC14-like protein, and (ii) a cognate ligand of said SEC14-likeprotein, wherein preferably said equal number is 9 to 60, wherein saidmethod comprises the steps of (a) providing said SEC14-like protein inan aqueous solution I, wherein the concentration of said SEC14-likeprotein in said solution I is 1 μM to 5 mM, and wherein the pH of saidsolution I is 6 to 9; (b) providing said cognate ligand of SEC14-likeprotein in an aqueous solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM; and wherein said solution II comprises a detergent; (c) generating asolution III by combining said solution I and said solution II, whereinthe ratio of the concentration of said SEC14-like protein and theconcentration of said cognate ligand of said SEC14-like protein in saidsolution III is of between 4:1 to 1:4 (molar/molar); (d) removing saiddetergent from said solution III, wherein removing said detergent fromsaid solution III allows said SEC14-like protein and said cognate ligandof said SEC14-like protein to assemble into a nanosphere; (e) separatingsaid nanosphere from said solution III; (f) optionally purifying saidnanosphere. Further preferred embodiment of the inventive methodsinclude the preferred and very preferred embodiments of the inventivenanosphere. In particular, in a very preferred embodiment, said equalnumber is a multiple of 3, and wherein preferably said number is of 3 to60, and wherein said human SEC14-like protein is selected from (a)α-tocopherol transfer protein (α-TTP); (b) Cellular retinaldehydebinding protein (CRALBP); (c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2);and (e) alpha-tocopherol transfer protein like (TTPAL).

Further preferred embodiment of the inventive methods include thepreferred and very preferred embodiments of the inventive nanosphere.

In a further preferred embodiment, the concentration of said SEC14-likeprotein in said solution I is 0.1 mM to 1 mM, and further preferably theconcentration of said SEC14-like protein in said solution I is 0.25 mMto 0.75 mM. In a further preferred embodiment, the pH of said solution Iis 7 to 8.

In a further preferred embodiment, said concentration of said cognateligand of SEC14-like protein in said solution I is 30 μM to 300 mM,further preferably the concentration of said cognate ligand ofSEC14-like protein in said solution I is 200 μM to 200 mM.

For this inventive method, said solution II comprises a detergent. Thedetergent serves to solubilize said cognate ligand of SEC14-like proteinin said solution II. In a preferred embodiment of the present invention,said detergent is selected from a non-ionic detergent or an anionicdetergent. Preferably said non-ionic detergent is selected from octylbeta-D-glucoside, nonyl beta-D-glucoside, decyl beta-D-glucoside, nonylbeta-D-maltoside, decyl beta-D-maltoside, undecyl beta-D-maltoside,dodecyl beta-D-maltoside, Tween 20®, Tween 40®, Tween 80® Triton X100®,Nonidet P40, polyethylenglycol 200. Preferably said anionic detergent isselected from sodium cholate, sodium deoxycholate, sodium glycocholate,sodium deoxyglycocholate and sodium taurocholate.

In a further preferred embodiment, said non-ionic detergent is selectedfrom octyl beta-D-glucoside, nonyl beta-D-glucoside, decylbeta-D-glucoside, nonyl beta-D-maltoside, decyl beta-D-maltoside,undecyl beta-D-maltoside, dodecyl beta-D-maltoside, Tween 20®, Tween40®, Tween 80® Triton X100®, Nonidet P40, polyethylenglycol 200.

In a further very preferred embodiment, said anionic detergent isselected from sodium cholate, sodium deoxycholate, sodium glycocholate,sodium deoxyglycocholate and sodium taurocholate. In a very preferredembodiment, said detergent is an anionic detergent, wherein said anionicdetergent is sodium cholate.

The concentration of said detergent used in said solution II can bedetermined by the skilled person in the art and is based on theknowledge the skilled person in the art since in order to solubilizesaid cognate ligand of SEC14-like protein in said solution II theconcentration is dependent on the nature of the detergent used.Typically and preferably the concentration of said detergent in saidsolution II is higher the critical micelle concentration (CMC) of saiddetergent, typically and preferably of said non-ionic detergent or saidanionic detergent. Typically and preferably the critical micelleconcentration (CMC) of said detergent, typically and preferably ofnon-ionic detergent or said anionic detergent is equal or higher than0.5 mM, and wherein further preferably the critical micelleconcentration (CMC) of said non-ionic detergent or said anionicdetergent is equal or higher than 10 mM.

In a further preferred embodiment, the ratio of the concentration ofsaid SEC14-like protein and the concentration of said cognate ligand ofsaid SEC14-like protein in said solution III is of between 3:1 to 1:3(molar/molar), and preferably the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 2:1 to 1:2(molar/molar).

In a further preferred embodiment, said removing of said detergent fromsaid solution III is performed by dialysis; and wherein preferably saidremoving of said detergent from said solution III by dialysis isperformed across a membrane, wherein preferably said membrane comprisesa molecular weight cut off of 1 to 25 kD, preferably of 5 to 20 kD, andagain further preferably of 10-15 kD. The dialysis is preferablyperformed with a first buffer, wherein said first buffer comprises ahalogenide of an alkaline metal, wherein preferably said halogenide ofan alkaline metal is potassium chloride or sodium chloride, and whereinfurther preferably said halogenide of an alkaline metal is sodiumchloride, wherein preferably the concentration of said halogenide of analkaline metal, preferably said sodium chloride in said first buffer is1 to 1000 mM, preferably 10 to 500 mM, more preferably 50 to 250 mM,most preferably 100-200 mM.

The dialysis is preferably performed at a temperature of 4° C. to 37°C., and wherein preferably said dialysis is performed over a period of 4to 24 h.

In a further preferred embodiment, said separating said nanosphere fromsaid solution III is effected by size exclusion chromatography oranionic exchange chromatography, preferably by size exclusionchromatography.

In a further preferred embodiment, said purifying said nanosphere iseffected by size exclusion chromatography or anionic exchangechromatography, preferably by size exclusion chromatography.

In again a further aspect, the present invention provides for a methodof producing a nanosphere comprising, preferably consisting of, an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein; wherein said method comprises the steps of (a)providing said SEC14-like protein in an aqueous solution I, wherein theconcentration of said SEC14-like protein in said solution I is 1 μM to 5mM, and wherein the pH of said solution I is 6 to 9, and whereinpreferably said solution I comprises a salt, wherein the concentrationof said salt is 10 mM to 500 mM; (b) providing said cognate ligand ofSEC14-like protein in a solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM, and wherein the solvent of said solution II is a water solublesolvent; (c) generating a solution III by combining said solution I andsaid solution II, wherein the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 4:1 to 1:4(molar/molar), and wherein the volume of said water soluble solvent insaid solution III is of between 0.5-8% (vol/vol); (d) allowing saidSEC14-like protein and said cognate ligand of said SEC14-like protein toform monomeric complexes consisting of one of said SEC14-like proteinand one of said cognate ligand of said SEC14-like protein; (e)separating said monomeric complexes from said solution III; (f)optionally purifying said monomeric complexes; (g) generating an aqueoussolution IV, wherein said solution IV comprises said monomericcomplexes, and wherein the concentration of said monomeric complex insaid solution IV is 5 mg/ml to 50 mg/ml; and wherein the pH of saidsolution IV is 6 to 9, and wherein preferably said solution IV comprisesa salt, wherein the concentration of said salt is 10 mM to 500 mM; (h)allowing said monomeric complexes to form crystals of said nanosphere.

Further preferred embodiment of the inventive methods include thepreferred and very preferred embodiments of the inventive nanosphere.

In a further preferred embodiment, the concentration of said SEC14-likeprotein in said solution I is 0.1 mM to 1 mM, and further preferably theconcentration of said SEC14-like protein in said solution I is 0.25 mMto 0.75 mM.

In a further preferred embodiment, the pH of said solution I is 7 to 8.Preferably said solution I comprises a salt, wherein the concentrationof said salt is 10 mM to 500 mM. Further preferred, the concentration ofsaid salt is 30 mM to 350 mM, and further preferably the concentrationof said salt is 100 mM to 250 mM.

In a further preferred embodiment, said salt is selected from a mono-,di-, tri- or tetravalent inorganic or organic salt, and wherein furtherpreferably said salt is selected from a di-, tri- or tetravalentinorganic or organic salt, and wherein again further preferably saidsalt comprises a divalent, tri, or tetravalent anion selected from HPO₄²⁻, SO₄ ²⁻, tartrate, malonate, D-myo-inositol 1,4,5-triphosphate andD-myo-inositol 1,3,4,5-tetrakis(phosphate) potassium salt.

In a further preferred embodiment, said concentration of said cognateligand of SEC14-like protein in said solution I is 30 μM to 300 mM,further preferably the concentration of said cognate ligand ofSEC14-like protein in said solution I is 200 μM to 200 mM.

The solvent of said solution II is a water soluble solvent. It is withinthe scope of the present invention that the water soluble solvent usedfor solution II may comprise minor amounts, i.e. up to 10% (v/v) ofwater even though typically and preferably said water soluble solventdoes not comprise any additional amounts of water other than the minoramount of water typically comprised in said water soluble solvent whensupplied by the manufacturer. Further preferably, said water solublesolvent dose not comprise more than 8% (v/v), preferably more than 7%(v/v), further preferably more than 5% (v/v) of water.

In a preferred embodiment of the present invention, said water solublesolvent is selected from methanol, ethanol, isopropanol, propanol,butanol, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), dioxan,methylpentane diol and glycerol; further preferably said water solublesolvent is selected from ethanol, isopropanol and dimethyl sulfoxide(DMSO).

In a preferred embodiment of the present invention, said ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 3:1 to 1:3 (molar/molar), and preferably the ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 2:1 to 1:2 (molar/molar).

In another preferred embodiment of the present invention, said volume ofsaid water soluble solvent in said solution III is of between 1-5%(vol/vol), and preferably the volume of said water soluble solvent insaid solution III is of between 2-4% (vol/vol).

In another preferred embodiment of the present invention, said allowingsaid SEC14-like protein and said cognate ligand of said SEC14-likeprotein to form said monomeric complexes is effected by keeping saidsolution III at a temperature of 4-37° C., preferably at roomtemperature, for a period of 1 h to 24 h, preferably for a period of 12to 24 h.

In another preferred embodiment of the present invention, saidseparating said monomeric complexes from said solution III is effectedby size exclusion chromatography or anionic exchange chromatography,preferably by size exclusion chromatography.

In another preferred embodiment of the present invention, said purifyingsaid monomeric complexes is effected by size exclusion chromatography oranionic exchange chromatography, preferably by size exclusionchromatography.

In another preferred embodiment of the present invention, theconcentration of said monomeric complex in said solution IV is 10 mg/mlto 40 mg/ml, and preferably the concentration of said monomeric complexin said solution IV is 10 mg/ml to 30 mg/ml, and further preferably theconcentration of said monomeric complex in said solution IV is 12 mg/mlto 22 mg/ml. Preferably, the pH of said solution IV is 7 to 8, furtherpreferably the pH of said solution IV is 7.2 to 7.8.

In another preferred embodiment, said solution IV comprises a salt,wherein the concentration of said salt is 10 mM to 500 mM; andpreferably said salt is selected from a mono-, di-, tri- or tetravalentinorganic or organic salt. Further preferably said salt is selected froma di-, tri-, or tetravalent inorganic or organic salt, and again furtherpreferably said salt comprises a divalent, tri, or tetravalent anionselected from HPO₄ ²⁻, SO₄ ²⁻, tartrate, malonate, D-myo-inositol1,4,5-triphosphate and D-myo-inositol 1,3,4,5-tetrakis(phosphate)potassium salt.

In another preferred embodiment, said solution IV comprises PEG, whereinthe concentration of said PEG is 1% v/v to 30% v/v; and whereinpreferably said PEG has a weight average molecular weight of betweenfrom 200 to 30′000, further preferably from 200 to 20000 including PEG200, 400, 800, 2000, 3350 4000, 8000, 12000, 16000.

Said salt and said PEG when comprised in said solution IV represent anamphiphilic precipitant being beneficial and preferred for said solutionIV of the present invention. Amphiphilic precipitants and mixtures ofamphiphilic precipitants like the preferred one of the present inventionare known to the skilled person in the art. Other amphiphilicprecipitants and mixtures of amphiphilic precipitants are encompassedwithin the present invention.

In another preferred embodiment, said allowing said monomeric complexesto form crystals of said nanosphere is effected at constant temperatureof 4° C.-37° C., wherein said constant temperature is preferably from10° C.-20° C. and wherein said temperature is further preferably from16° C.-19° C.

In a further aspect, the present invention provides for a method ofproducing the inventive nanosphere as described herein, wherein saidnanosphere comprises, preferably consists of, an equal number of (i) ahuman SEC14-like protein, and (ii) a cognate ligand of said SEC14-likeprotein, wherein preferably said equal number is 3 to 60, wherein saidmethod comprises the steps of (a) providing said SEC14-like protein inan aqueous solution I, wherein the concentration of said SEC14-likeprotein in said solution I is 1 μM to 5 mM, and wherein the pH of saidsolution I is 6 to 9; (b) providing said cognate ligand of SEC14-likeprotein in an aqueous solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM; and wherein said solution II comprises a detergent; (c) generating asolution III by combining said solution I and said solution II, whereinthe ratio of the concentration of said SEC14-like protein and theconcentration of said cognate ligand of said SEC14-like protein in saidsolution III is of between 4:1 to 1:4 (molar/molar); (d) removing saiddetergent from said solution III, wherein removing said detergent fromsaid solution III allows said SEC14-like protein and said cognate ligandof said SEC14-like protein to form monomeric complexes consisting of oneof said SEC14-like protein and one of said cognate ligand of saidSEC14-like protein; (e) separating said monomeric complexes from saidsolution III; (f) optionally purifying said monomeric complexes; (g)generating an aqueous solution IV, wherein said solution IV comprisessaid monomeric complexes, and wherein the concentration of saidmonomeric complex in said solution IV is 5 mg/ml to 50 mg/ml, andwherein the pH of said solution IV is 6 to 9, and wherein preferablysaid solution IV comprises a salt, and wherein the concentration of saidsalt is 10 mM to 500 mM; (h) allowing said monomeric complexes to formcrystals of said nanosphere. Further preferred embodiment of theinventive methods include the preferred and very preferred embodimentsof the inventive nanosphere. In particular, in a very preferredembodiment, said equal number is a multiple of 3, and wherein preferablysaid number is of 3 to 60, and wherein said human SEC14-like protein isselected from (a) α-tocopherol transfer protein (α-TTP); (b) Cellularretinaldehyde binding protein (CRALBP); (c) Clavesin1 (CLVS1); (d)Clavesin2 (CLVS2); and (e) alpha-tocopherol transfer protein like(TTPAL).

In a further aspect, the present invention provides for a method ofproducing the inventive nanosphere as described herein, wherein saidnanosphere comprises, preferably consists of, an equal number of (i) ahuman SEC14-like protein, and (ii) a cognate ligand of said SEC14-likeprotein, wherein preferably said equal number is 9 to 60, wherein saidmethod comprises the steps of (a) providing said SEC14-like protein inan aqueous solution I, wherein the concentration of said SEC14-likeprotein in said solution I is 1 μM to 5 mM, and wherein the pH of saidsolution I is 6 to 9; (b) providing said cognate ligand of SEC14-likeprotein in an aqueous solution II, wherein the concentration of saidcognate ligand of SEC14-like protein in said solution I is 5 μM to 500mM; and wherein said solution II comprises a detergent; (c) generating asolution III by combining said solution I and said solution II, whereinthe ratio of the concentration of said SEC14-like protein and theconcentration of said cognate ligand of said SEC14-like protein in saidsolution III is of between 4:1 to 1:4 (molar/molar); (d) removing saiddetergent from said solution III, wherein removing said detergent fromsaid solution III allows said SEC14-like protein and said cognate ligandof said SEC14-like protein to form monomeric complexes consisting of oneof said SEC14-like protein and one of said cognate ligand of saidSEC14-like protein; (e) separating said monomeric complexes from saidsolution III; (f) optionally purifying said monomeric complexes; (g)generating an aqueous solution IV, wherein said solution IV comprisessaid monomeric complexes, and wherein the concentration of saidmonomeric complex in said solution IV is 5 mg/ml to 50 mg/ml, andwherein the pH of said solution IV is 6 to 9, and wherein preferablysaid solution IV comprises a salt, and wherein the concentration of saidsalt is 10 mM to 500 mM; (h) allowing said monomeric complexes to formcrystals of said nanosphere. Further preferred embodiment of theinventive methods include the preferred and very preferred embodimentsof the inventive nanosphere. In particular, in a very preferredembodiment, said equal number is a multiple of 3, and wherein preferablysaid number is of 3 to 60, and wherein said human SEC14-like protein isselected from (a) α-tocopherol transfer protein (α-TTP); (b) Cellularretinaldehyde binding protein (CRALBP); (c) Clavesin1 (CLVS1); (d)Clavesin2 (CLVS2); and (e) alpha-tocopherol transfer protein like(TTPAL).

Further preferred embodiment of the inventive methods include thepreferred and very preferred embodiments of the inventive nanosphere.

In a further preferred embodiment, the concentration of said SEC14-likeprotein in said solution I is 0.1 mM to 1 mM, and further preferably theconcentration of said SEC14-like protein in said solution I is 0.25 mMto 0.75 mM. In a further preferred embodiment, the pH of said solution Iis 7 to 8.

In a further preferred embodiment, said concentration of said cognateligand of SEC14-like protein in said solution I is 30 μM to 300 mM,further preferably the concentration of said cognate ligand ofSEC14-like protein in said solution I is 200 μM to 200 mM.

For this inventive method, said solution II comprises a detergent. Thedetergent serves to solubilize said cognate ligand of SEC14-like proteinin said solution II. In a preferred embodiment of the present invention,said detergent is selected from a non-ionic detergent or an anionicdetergent. Preferably said non-ionic detergent is selected from octylbeta-D-glucoside, nonyl beta-D-glucoside, decyl beta-D-glucoside, nonylbeta-D-maltoside, decyl beta-D-maltoside, undecyl beta-D-maltoside,dodecyl beta-D-maltoside, Tween 20®, Tween 40®, Tween 80® Triton X100®,Nonidet P40, polyethylenglycol 200. Preferably said anionic detergent isselected from sodium cholate, sodium deoxycholate, sodium glycocholate,sodium deoxyglycocholate and sodium taurocholate.

In a further preferred embodiment, said non-ionic detergent is selectedfrom octyl beta-D-glucoside, nonyl beta-D-glucoside, decylbeta-D-glucoside, nonyl beta-D-maltoside, decyl beta-D-maltoside,undecyl beta-D-maltoside, dodecyl beta-D-maltoside, Tween 20®, Tween40®, Tween 80® Triton X100®, Nonidet P40, polyethylenglycol 200.

In a further very preferred embodiment, said anionic detergent isselected from sodium cholate, sodium deoxycholate, sodium glycocholate,sodium deoxyglycocholate and sodium taurocholate. In a very preferredembodiment, said detergent is an anionic detergent, wherein said anionicdetergent is sodium cholate.

The concentration of said detergent used in said solution II can bedetermined by the skilled person in the art and is based on theknowledge the skilled person in the art since in order to solubilizesaid cognate ligand of SEC14-like protein in said solution II theconcentration is dependent on the nature of the detergent used.Typically and preferably the concentration of said detergent in saidsolution II is higher the critical micelle concentration (CMC) of saiddetergent, typically and preferably of said non-ionic detergent or saidanionic detergent. Typically and preferably the critical micelleconcentration (CMC) of said detergent, typically and preferably ofnon-ionic detergent or said anionic detergent is equal or higher than0.5 mM, and wherein further preferably the critical micelleconcentration (CMC) of said non-ionic detergent or said anionicdetergent is equal or higher than 10 mM.

In a further preferred embodiment, the ratio of the concentration ofsaid SEC14-like protein and the concentration of said cognate ligand ofsaid SEC14-like protein in said solution III is of between 3:1 to 1:3(molar/molar), and preferably the ratio of the concentration of saidSEC14-like protein and the concentration of said cognate ligand of saidSEC14-like protein in said solution III is of between 2:1 to 1:2(molar/molar).

In a further preferred embodiment, said removing of said detergent fromsaid solution III is performed by dialysis; and wherein preferably saidremoving of said detergent from said solution III by dialysis isperformed across a membrane, wherein preferably said membrane comprisesa molecular weight cut off of 1 to 25 kD, preferably of 5 to 20 kD, andagain further preferably of 10-15 kD. The dialysis is preferablyperformed with a first buffer, wherein said first buffer comprises ahalogenide of an alkaline metal, wherein preferably said halogenide ofan alkaline metal is potassium chloride or sodium chloride, and whereinfurther preferably said halogenide of an alkaline metal is sodiumchloride, wherein preferably the concentration of said halogenide of analkaline metal, preferably said sodium chloride in said first buffer is1 to 1000 mM, preferably 10 to 500 mM, more preferably 50 to 250 mM,most preferably 100-200 mM.

The dialysis is preferably performed at a temperature of 4° C. to 37°C., and wherein preferably said dialysis is performed over a period of 4to 24 h.

In a further preferred embodiment, said separating said monomericcomplexes from said solution III is effected by size exclusionchromatography or anionic exchange chromatography, preferably by sizeexclusion chromatography.

In a further preferred embodiment, said purifying said monomericcomplexes is effected by size exclusion chromatography or anionicexchange chromatography, preferably by size exclusion chromatography.

In another preferred embodiment of the present invention, theconcentration of said monomeric complex in said solution IV is 10 mg/mlto 40 mg/ml, and preferably the concentration of said monomeric complexin said solution IV is 10 mg/ml to 30 mg/ml, and further preferably theconcentration of said monomeric complex in said solution IV is 12 mg/mlto 22 mg/ml. Preferably, the pH of said solution IV is 7 to 8, furtherpreferably the pH of said solution IV is 7.2 to 7.8.

In another preferred embodiment, said solution IV comprises a salt,wherein the concentration of said salt is 10 mM to 500 mM; andpreferably said salt is selected from a mono-, di-, tri- or tetravalentinorganic or organic salt. Further preferably said salt is selected froma di-, tri-, or tetravalent inorganic or organic salt, and again furtherpreferably said salt comprises a divalent, tri, or tetravalent anionselected from HPO₄ ²⁻, SO₄ ²⁻, tartrate, malonate, D-myo-inositol1,4,5-triphosphate and D-myo-inositol 1,3,4,5-tetrakis(phosphate)potassium salt.

In another preferred embodiment, said solution IV comprises PEG, whereinthe concentration of said PEG is 1% v/v to 30% v/v; and whereinpreferably said PEG has a weight average molecular weight of betweenfrom 200 to 30′000, further preferably from 200 to 20000 including PEG200, 400, 800, 2000, 3350 4000, 8000, 12000, 16000.

Said salt and said PEG when comprised in said solution IV represent anamphiphilic precipitant being beneficial and preferred for said solutionIV of the present invention. Amphiphilic precipitants and mixtures ofamphiphilic precipitants like the preferred one of the present inventionare known to the skilled person in the art. Other amphiphilicprecipitants and mixtures of amphiphilic precipitants are encompassedwithin the present invention.

In another preferred embodiment, said allowing said monomeric complexesto form crystals of said nanosphere is effected at constant temperatureof 4° C.-37° C., wherein said constant temperature is preferably from10° C.-20° C. and wherein said temperature is further preferably from16° C.-19° C.

Typically and preferably, said SEC14-like protein is obtained byheterologous expression of said SEC14-like protein in a host, whereinpreferably said host is E. coli, and wherein optionally saidheterologously expressed SEC14-like protein is purified, preferably byaffinity chromatography, further preferably by affinity chromatographyon Ni-NTA resin.

In again a further aspect, the present invention provides for apharmaceutical composition comprising (a) the nanosphere of the presentinvention; and (b) a pharmaceutically acceptable carrier.

In another aspect, the present invention provides for the nanosphere orthe pharmaceutical composition in accordance with present invention foruse as a medicament.

In again a further aspect, the present invention provides for thenanosphere or the pharmaceutical composition of the present inventionfor use in a method of the treatment or prevention, preferably of thetreatment, of Ataxia with Vitamin E Deficiency (AVED), muscle dystrophy,hypolipidemia, hypolipoproteinemia, dyslipidemia, human infertility,impaired wound healing or an inflammatory disease, wherein preferablysaid inflammatory disease is arthritis. Preferably said method oftreatment or prevention is for a human. Further preferred is saidprevention in elderly human.

In a further preferred embodiment of the present invention, saidnanosphere or said pharmaceutical composition in accordance with thepresent invention is for use in a method of the treatment or prevention,preferably of the treatment, of Ataxia with Vitamin E Deficiency (AVED),muscle dystrophy, hypolipidemia, hypolipoproteinemia, dyslipidemia,human infertility, impaired wound healing or an inflammatory disease,wherein preferably said inflammatory disease is arthritis.

In another aspect, the present invention provides for the nanosphere orthe pharmaceutical composition in accordance with present invention foruse in a method of treating or preventing a disease alleviated byincreasing the level of Vitamin E in a human, wherein preferably saiddisease is Ataxia with Vitamin E Deficiency (AVED), muscle dystrophy,hypolipidemia, hypolipoproteinemia, dyslipidemia, human infertilityimpaired wound healing, or an inflammatory disease, and wherein furtherpreferably said inflammatory disease is arthritis, and wherein saidhuman SEC14-like protein is selected from α-tocopherol transfer protein(α-TTP).

The treatment and/or prevention of wound healing in accordance with thepresent invention, is preferably believed to be beneficial to increasekeloid formation after surgery reduce.

In another aspect, the present invention provides for the nanosphere orthe pharmaceutical composition in accordance with present invention foruse in a method of treating or preventing a disease alleviated byincreasing the level of Vitamin A in a human, wherein preferably saiddisease is an eye disease or human infertility, and wherein said humanSEC-14 like protein is Cellular retinaldehyde binding protein (CRALBP).

The treatment and/or prevention of human fertility in accordance withthe present invention, and, thus, in particular the treatment and/orprevention of a couple's inability to conceive, is believed to bebeneficial to reduce an/or eliminate the impairment of either the femaleuterine function or the sperm count or sperm motility.

In another aspect, the present invention provides for the use of thenanosphere or the use of the pharmaceutical composition in accordancewith present invention in the manufacture of a medicament for thetreatment or prevention, preferably of the treatment, of Ataxia withVitamin E Deficiency (AVED), muscle dystrophy, hypolipidemia,hypolipoproteinemia, dyslipidemia, human infertility, impaired woundhealing or an inflammatory disease, wherein preferably said inflammatorydisease is arthritis.

In another aspect, the present invention provides for the use of thenanosphere or the use of the pharmaceutical composition in accordancewith present invention for the treatment or prevention, preferably ofthe treatment, of Ataxia with Vitamin E Deficiency (AVED), muscledystrophy, hypolipidemia, hypolipoproteinemia, dyslipidemia, humaninfertility, impaired wound healing or an inflammatory disease, whereinpreferably said inflammatory disease is arthritis.

In another aspect, the present invention provides for a method oftreatment and/or prevention, preferably of treatment, of Ataxia withVitamin E Deficiency (AVED), muscle dystrophy, hypolipidemia,hypolipoproteinemia, dyslipidemia, human infertility, impaired woundhealing or an inflammatory disease, wherein preferably said inflammatorydisease is arthritis, in a human, said method comprising administeringto said human an effective amount of the nanosphere or thepharmaceutical composition in accordance with present invention.

In another aspect, the present invention provides for the nanosphere orthe pharmaceutical composition in accordance with present invention foruse in a method of treating or preventing a disease alleviated byincreasing the level of Vitamin A in a human, wherein preferably saiddisease is an eye disease and wherein said human SEC14-like protein isCellular retinaldehyde binding protein (CRALBP).

In another aspect, the present invention provides for a nanosphereobtainable by any one of the inventive methods of the present invention,wherein said nanosphere comprises, preferably consists of, an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein, wherein preferably said equal number is 3 to60. In a further very preferred embodiment, said equal number is amultiple of 3, and wherein preferably said number is of 3 to 60, andwherein said human SEC14-like protein is selected from (a) α-tocopheroltransfer protein (α-TTP); (b) Cellular retinaldehyde binding protein(CRALBP); (c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2); and (e)alpha-tocopherol transfer protein like (TTPAL).

In another aspect, the present invention provides for a nanosphereobtainable by any one of the inventive methods of the present invention,wherein said nanosphere comprises, preferably consists of, an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein, wherein preferably said equal number is 9 to60. In a further very preferred embodiment, said equal number is amultiple of 3, and wherein preferably said number is of 3 to 60, andwherein said human SEC14-like protein is selected from (a) α-tocopheroltransfer protein (α-TTP); (b) Cellular retinaldehyde binding protein(CRALBP); (c) Clavesin1 (CLVS1); (d) Clavesin2 (CLVS2); and (e)alpha-tocopherol transfer protein like (TTPAL).

EXAMPLES Example 1 Expression and Purification of Monomeric α-TTP

The N-terminal (His)₆-tagged α-TTP expression construct was made bycloning the PCR product derived from a human cDNA library into the NdeIand XhoI sites of the pET-28a vector (Stratagene, Calif. USA) using theprimers 5′-GGGAATTCGCAGAGGCGC-GATCCCAG-3′ (SEQ ID NO:1) and5′-CCGTCATTGAATGCTCTCAGAAATGC-3′ (SEQ ID NO:2). Protein expression wascarried out in Escherichia coli strain BL21(DE3) under control of the T7promoter. Transformed bacteria were grown at 37° C. to an opticaldensity (OD₆₀₀) of 0.8 and induced with 330 mMisopropyl-thiogalactopyranoside overnight at 30° C. Bacteria wereharvested by centrifuging at 7′300 g and 4° C. for 30 minutes. Bacterialpellets obtained from one liter of medium were re-suspended in 25 mllysis buffer (20 mM Tris, pH 8.0, 100 mM NaCl, 10 mM imidazole, 0.5(v/v) Triton X-100 and 1 mM phenylmethylsulfonyfluoride). Harvestedcells were disrupted twice in a French pressure cell. The lysate wascentrifuged at 39′000 g and 4° C. for 40 minutes. The clarifiedsupernatant was passed through a column containing 12 ml of TALONSuperflow (Clontech Laboratories, CA, USA). Non-specifically boundproteins were removed by rinsing the column with washing buffer (20 mMTris, 100 mM NaCl, 10 mM imidazole, pH 8.0) until the UV absorption at280 nm recovered the level of the base line. The protein was eluted withelution buffer (20 mM Tris, 100 mM NaCl, 150 mM imidazole, pH 8.0). The(His)₆-tag was cleaved off using thrombin (GE Healthcare, LittleChalfont, UK) in elution buffer (20 mM Tris, 100 mM NaCl, 150 mMimidazole, pH 8.0) at 4° C. overnight. The protein eluate was pooled andconcentrated using Vivaspin (Satorius, Goettingen, Del.) centrifugalconcentrators (MWCO 10 kDa) to ≤2.5 mg/ml in order to preventaggregation of apo-α-TTP.

Example 2 Preparation of Mixtures of Cognate Ligand-Complexes Composedof Monomeric α-TTP-α-Tol and of α-TTP-α-Tol Nanospheres Comprising α-TTPTrimers

The formation of α-TTP-α-Tol cognate ligand-complexes was achieved bydialysing freshly prepared apo-α-TTP in the presence of detergentsolubilized α-Tocopherol. In brief, a droplet of 1 mg of α-Tol wasoverlaid with 40.9 mg of solid sodium cholate and subsequently suspendedin 1 ml of elution buffer (20 mM Tris, 100 mM NaCl, 150 mM imidazole, pH8.0). The suspension was bath sonicated until all material had dissolvedto a clear solution. Apo-α-TTP (11 ml at ≤2.5 mg/ml) was complementedwith the tocopherol-sodium cholate solution at 9:1 (v/v) ratio andtransferred into a CelluSep T3 dialysis tubular membrane with an MWCOrange of 12-14 kDa (Membranes Filtration Products. TX, USA). Dialysiswas performed in two steps against 3 l buffer (20 mM Tris, 100 mM NaCl,pH 8.0) each for six hours at 4° C. The dialysate (12 ml) was filteredthrough a Millex GP 0.22 μm filter (EMD Milipore, Mass., USA),supplemented with Triton X-100 at a final concentration of 0.01% (v/v),reduced to 2 ml and separated by preparative size exclusionchromatography. Fractions corresponding to the size of the monomericα-TTP-α-Tol cognate ligand-complex were pooled and concentrated to 20mg/ml using Vivaspin concentrators (MWCO 10 kDa; Satorius, Goettingen,Del.) and directly used for crystallization. Fractions corresponding tothe size of α-TTP-α-Tol nanospheres comprising α-TTP trimers were pooledand concentrated using Vivaspin concentrators (MWCO 30 kDa) to 10 mg/mland re-purified by analytical size exclusion chromatography (SEC).

Example 3 Characterization of α-TTP-α-Tol Nanospheres Comprising α-TTPTrimers

A. Size Exclusion Chromatography

Preparative and analytical SEC of α-TTP-α-Tol nanospheres was performedon HiLoad 16/60 Supersose 75 prep grade and on Superose 6 10/300 columnsrespectively (GE Healthcare, Little Chalfont, UK), both attached to anAEKTA Purifier chromatography system (GE Healthcare, Little Chalfont,UK). Runs were performed in SEC buffer (10 mM Tris, 100 mM NaCl, pH 8.0)at flow rates ranging from 0.5 (analytical) to 1.5 ml/minute(preparative) at 6° C. SEC columns were calibrated using commerciallyavailable protein calibration kits (GE Healthcare, Little Chalfont, UK)(FIG. 1).

B. Negative-Stain Transmission Electron Microscopy

A sample of α-TTP-α-Tol nanospheres at a concentration of 300 μg/ml wasadsorbed for 1 minute to parlodion carbon-coated copper grids, whichwere previously rendered hydrophilic by glow discharge at low pressurein air. After adsorption the grids were washed with three drops ofdouble-distilled water and stained with two drops of 0.75% uranylformate. Electron micrographs were recorded with a Philips CM12transmission electron microscope operated at 80 kV and equipped with aMorada CCD camera (Soft Imaging System). Image analysis was performedwith the ImageJ image processing program V1.490 (NIH, MD, USA) (FIG. 2).

C. Western Blotting

In brief, SDS-PAGE was carried out on 12% PAGE gels. Prior to blottingon nitrocellulose membranes gels were incubated for 20 minutes intransfer buffer (25 mM Tris, 192 mM glycine, 20% methanol, pH 8.3).Blotting was carried out at 130 mA for 50 minutes using a semi-dryblotting apparatus (Bio-Rad Laboratories, CA, USA). For analysis acommercially available primary antibody against α-TTP (alpha TTPAntibody [C2C3] C-term, GeneTex Inc., CA, USA) was used. IRDye secondaryantibodies from LI-COR were employed for visualization with either IRDye800CW or IRDye 680RD and scans were performed on a LI-COR Odysseyinfrared system (LI-COR Biosystems, NE, USA) (FIG. 3).

D. Native Polyacrylamide Gel Electrophoresis

Native PAGE was performed using pre-cast NativePAGE Novex 4-16% Bis-TrisProtein Gels (Life Technologies, CA, USA). Each protein sample (20 μl,0.5 mg/ml) was mixed with an equal volume of native-PAGE loading buffer(62 mM Tris, 25% glycerol, 1% bromophenol blue, pH 6.8). Gels were runat 4° C. in running buffer (50 mM Tricine, 50 mM BisTris, pH 8.0) at160V for 30 minutes and then at 180V until the bromophenole blue markerreached the end of the gel. Protein visualization was achieved bystaining with SYPRO ruby protein gel stain (Life Technologies, CA, USA)(FIG. 4).

E. Dynamic Light Scattering

Freshly pooled fractions of α-TTP-α-Tol nanospheres (concentration range0.1-0.2 mg/ml) obtained from analytical SEC (10 mM Tris, 100 mM NaCl, pH8.0) were analysed by dynamic light scattering (DLS). Determination ofthe size distribution profile of each sample was performed on a DynaPromolecular sizing instrument (Protein-Solutions) using UVettes(Eppendorf, Hamburg, Del.) of 1 cm path length. Each data set wascollected for at least 5 minutes containing a minimum of 100 singlemeasurements. A hydrodynamic radius of 17.6±3.8 nm was obtained from DLStriplicate measurements.

F. Thermodynamic Analysis

A Jasco J-175 Spectropolarimeter with a Peltier PFD-350S temperaturecontroller was used to measure CD spectra and temperature-dependedprotein unfolding of apo-α-TTP, monomeric α-TTP and of α-TTP-α-Tolnanospheres. For this a 1 mm path length quartz cell (with 100 μlsample) was used and the protein concentration ranged from 0.1-0.5mg/ml. The response was set to 1 s with a bandwidth of 5 nm. Followingthe results from the CD spectra, the wavelength was adjusted to 222 nmfor temperature-dependent protein unfolding experiments. The temperaturewas increased at a rate of 2 K minute⁻¹ from 20° C. to 80° C., formonomeric α-TTP, and from 20° C. to 100° C., for α-TTP-α-Tolnanospheres, both in increments of 0.5 K. The transition temperatures(T_(m)) were calculated from the 1^(st) derivative of the unfoldingcurves (FIG. 5).

Example 4 Crystallization and Structure Determination of α-TTP-α-TolNanospheres Comprising α-TTP Trimers

The crystals were grown by either hanging or sitting-drop vapordiffusion using reservoir solutions ranging from 10 to 15% PEG-4000,100-175 mM ammonium sulfate in 100 mM Hepes sodium pH 7.5 at 18° C.Freshly prepared monomeric α-TTP cognate ligand-complex was used in aconcentration range between 12-22 mg/ml. Highest quality crystals offully reduced α-TTP-α-Tol nanospheres were observed within two weeks atdrop ratios of protein over reservoir ranging between 3/1 and 2/1 (v/v).Crystals had cubic shape with edge length ranging between 20 and 80 μm.Isomorphous crystals of fully oxidized α-TTP-α-Tol nanospheres werecollected after two months. All crystals were flash frozen in nitrogenafter adding glycerol in two steps to a final concentration of 20%(v/v). Diffraction data were collected at the Swiss Light Source (SLS)synchrotron beamline X06DA (PSI Villigen) at 100 K, employing a DectrisPilatus 2M CCD detector (DECTRIS Ltd., Baden, Switzerland). All datawere indexed, integrated and scaled with XDS (Kabsch W.; ActaCrystallographica Section D: Biological Crystallography. 201066:125-132). Phaser-MR was used for calculating the initial phases withthe truncated structure model (residues 47-275) of monomeric α-TTP (PDBID: 1OIP) as search structure. The atomic models of reduced α-TTP-α-Tolnanospheres and of oxidized α-TTP-α-Tol nanospheres were both refined byiterative cycles of manual model building using COOT (Emsley P, LohkampB, Scott W G, Cowtan K.; Acta Crystallographica Section D: BiologicalCrystallography. 2010 66:486-501) and restrained refinements using thePhenix programm suite (Adams P D, et al.; Acta Crystallographica SectionD: Biological Crystallography. 2010 66:213-221). Coordinates andstructure factors of both structures have been deposited in the RCSBProtein Data Bank with ID codes 5DI6 and 5DLU.

Example 5 Characterization of Protein-Protein Interactions Leading tothe Formation of α-TTP-α-Tol Nanospheres Comprising α-TTP Trimers

The α-TTP-α-Tol nanospheres crystallized exclusively when starting frommonodisperse solutions of monomeric α-TTP-α-Tol cognate ligand-complex.The nanosphere comprises 24 protomers, with one α-Tol bound to each,assembled into a spheroidal shell reminiscent of a viral capsid. TheX-ray structural model of α-TTP-α-Tol nanosphere, for both redox states,has an external diameter of 16.8 nm consistent in size with measurementson α-TTP-α-Tol particles from soluble preparations. The structure isfurther characterized by an apparently hollow cavity of 8.1 nm diameter.Closer inspection of the X-ray structural model of the particle revealeda topology of a twisted cantellated cube (point symmetry group 0,Schoenflies notation) taking the centers of each protein monomer asvertexes, and connecting them through protein-protein contactinterfaces. According to its point group, the nanosphere's symmetryoperations are proper rotations only around three C4, four C3 and six C2axes (FIG. 6).

Each α-TTP-α-Tol monomer is in contact with four first neighbors. Withtwo of such neighbors, it forms one of the eight trimeric interfacescrossed by the C3 symmetry axes, and with the second two neighbors it isinvolved in building up one of the six tetrameric interfaces crossed byone of the C4 axes. The tetrameric unit is completed by a secondneighbor unit, which is anyway not in direct contact. Twelve rhomboidalfaces complete the nano cage, each crossed by one of the C2 symmetryaxes. The two asymmetric edges of such interfaces correspond to those ofthe trimeric and tetrameric assemblies. Each monomer is involved in twoof these interfaces. The oxidized from of the α-TTP-α-Tol nanospherepresents here one disulphide bridge crosslinking C80 of two α-TTP-α-Tolunits through the rhombohedral channel. The oxidized α-TTP-α-Tolnanosphere thus contains at total of 12 S-S bridges covalently bindingall trimeric subunits. Oxidation is accompanied by local unwinding ofthe helical segment (aa's 65-79). It also induces structuring of theneighbouring C-terminus (aa's 275-278) into a regular α-helical motif.No other significant structural differences are observed between thereduced and oxidized forms of α-TTP-α-Tol nanospheres.

The highly packed trimeric interface is constituted by severalprotein-protein contacts. Each unit interacts with the following onethrough the helical segment 49-56, the 57-64 loop, and the first turn ofthe helical segment 65-79, as well as with residue R151. The partnerprotein interacts with the amino acids 67-74 in the helical segment65-79, and with the C-terminal residues (aa's 275 to 278) (FIG. 7).

The trimeric interface is characterized by hydrophobic packing andfurther stabilized by salt bridges. These electrostatic interactions arelocalized mostly at the exterior of the interface, with residues R57 andR151 on one protein interacting with the C-terminus of the facing unit.Residues D64 and K71 constitute one additional salt bridge (3.87 Å,localized closer to the core of the interface. At the very center, thethree W67 residues interact with each other in T-shape by van der Waalsstacking. To our observation, this is the only contact point involvingmore than two proteins in the whole α-TTP-α-Tol nanosphere.

W67 together with L63, F61 and L56 constitute a classical “hot-spot”that accounts for roughly three quarters (77%) of the interface'soverall binding free energy (Clackson T, Wells J A. Science 1995267:383-386).

Example 6 Identification of a Conserved Sequence Pattern within theProtein-Protein Interaction Motif Leading to the Trimeric Forms ofα-TTP-α-Tol Nanospheres

3-D superimposition of the α-TTP-α-Tol monomer with protomers of theα-TTP-α-Tol nanosphere evidenced that in monomeric α-TTP-α-Tol thetrimeric interface is not exposed to the solvent due to folding of theN-terminal segment (aa's 1-47). Comparison of the known structures ofthe different members of the SEC14-like family evidenced that theN-terminal segment 1-47 was not always fully detected by X-rayscattering, indicating that this portion of the protein is lessstructured and more prone to refolding (Sha B1, Phillips S E, BankaitisV A, Luo M., Nature. 1998 391:506-10; Meier R, Tomizaki T,Schulze-Briese C, Baumann U, Stocker A., J Mol Biol 2003 331: 725-734;He X, Lobsiger J, Stocker A., Proceedings of the National Academy ofSciences 2009 106:18545-18550; Christen M, et al., Journal of structuralbiology 2015 190:261-270). It was concluded that formation of trimericassemblies requires unmasking of the trimerization motif by displacingthe N-terminal tail of α-TTP in the outer space of the α-TTP-α-Tolnanosphere. Accordingly, the 1-47 segment was not detected in thestructure on the nanosphere, probably due to conformational disorder.

Analysis of the secondary structure by using the PSIPRED web serviceindicated that corresponding helix turn helix motifs of α-TTP (aa's47-90) and of CRALBP (aa's 91-123) are highly similar. Within the motifa characteristic sequence pattern of mostly hydrophobic residues wasdetermined that leads to the trimeric forms within the α-TTP-α-Tolnanospheres (FIG. 8). Primary sequence alignment of the N-terminalsegment of α-TTP (aa's 47-90) with corresponding segments of relatedSEC14-like proteins by the Multalin webservice (Corpet, F., NucleicAcids Res. 1988 16:10881-10890) revealed a high degree of conservationfor residues within the helical segment 49-56, the 57-64 loop, and thefirst turn of the helical segment 65-79 (FIG. 8).

The sequences of human origin used for MULTALIN alignment were:sp|P49638|TTPA HUMAN Alpha-tocopherol transfer protein, sp|Q9BTX7|TTPALHUMAN Alpha-tocopherol transfer protein-like, sp|Q8IUQ0|CLVS1_HUMANClavesin-1, sp|Q5SYC1|CLVS2_HUMAN Clavesin-2 and sp|P12271|RLBP1_HUMANRetinaldehyde-binding protein 1 (FIG. 9).

Example 7 Expression and Purification of Monomeric CRALBP

Human RLBP1 cDNA was obtained from Deutsches Ressourcenzentrum fürGenomforschung GmbH (JRAUp969D1020D). The N-terminal (His)₆-taggedCRALBP overexpression vector was constructed by cloning into the NdeIand XhoI sites of the pET-28a vector (Stratagene). The N-terminal(His)₆-tagged construct was transformed into E. coli BL21 (DE3)(Invitrogen). Cells were cultured overnight with agitation at 37° C. in120 mL LB medium containing 30 ug/mL kanamycin. The overnight culturewas used to inoculate 6 L of LB medium (30 ug/mL kanamycin). The culturewas grown at 20° C. to an OD600 of 0.7 and then was induced with 1 mMisopropyl-thiogalactopyranoside for 16 h. Cells were harvested bycentrifugation at 5000 g for 45 min and were resuspended in 250 mL ofice-cold lysis buffer (20 mM imidazole; 100 mM NaCl; 20 mM Tris-HCl, pH7.4; 1% wt/vol Triton X-100). The cells were disrupted byultrasonication for 20 min, and the lysate was centrifuged at 20,000 gfor 35 min to remove debris. The (His)₆-tagged CRALBP was purified fromthe supernatant by affinity chromatography on 10 mL of Ni-NTA SUPERFLOW(Qiagen) according to the manufacturer's instructions. Briefly, thelysate was loaded on the column previously equilibrated in lysis buffer,was washed with 200 mL of lysis buffer, and was eluted in 35 mL ofelution buffer (20 mM Tris-HCl, pH 7.4; 200 mM imidazole; 100 mM NaCl).Typical yields were 35-40 mg of pure CRALBP as judged by SDS/PAGE. Theprotein eluate was pooled and concentrated using Vivaspin (Satorius,Goettingen, Del.) centrifugal concentrators (MWCO 10 kDa) to ≤10 mg/mlin order to prevent aggregation of apo-CRALBP.

Example 8 Preparation of Mixtures Composed of Cognate Ligand-Complexesof Monomeric CRALBP-11-Cis-Retinal and of CRALBP-11-Cis-RetinalHomo-Oligomers

All procedures involving 11-cis-retinal were performed under dim redillumination (40-W ruby bulbs) at 4° C. unless specified. CRALBP wasbound to 11-cis-retinal (1.5-fold molar excess over CRALBP) by addingthe ligand at a concentration 16.7 mM in the presence of sodium cholate(55.7 mM) and incubating the mixture for 15 min at 4° C. Alternatively,CRALBP was bound to 11-cis-retinal (1.5-fold molar excess over CRALBP)by adding the ligand at a concentration 16.7 mM in ethanol andincubating the mixture for 15 min or up to 45 min at 4° C. The(His)₆-tag was cleaved by adding 20 units of thrombin protease (GEHealthcare) and subsequent incubation at 4° C. overnight. The proteinsolution was then passed through a Ni-NTA column to remove uncleavedmaterial. The flowthrough was concentrated by Centriprep-10 (Millipore)to 20 mg/mL. Cognate ligand-complexes of CRALBP were separated on aSuperose 6 SEC column (GE Healthcare).

Example 9 Preparation of Mixtures Composed of Cognate Ligand-Complexesof Monomeric CRALBP-9-Cis-Retinal and of CRALBP-9-Cis-RetinalHomo-Oligomers

All procedures involving 9-cis-retinal were performed under dim redillumination (40-W ruby bulbs) at 4° C. unless specified. CRALBP wasbound to 9-cis-retinal (1.5-fold molar excess over CRALBP) by adding theligand at a concentration 16.7 mM in the presence of sodium cholate(55.7 mM) and incubating the mixture for 15 min at 4° C. Alternatively,CRALBP was bound to 9-cis-retinal (1.5-fold molar excess over CRALBP) byadding the ligand at a concentration 16.7 mM in ethanol and incubatingthe mixture for 15 min at 4° C. The (His)₆-tag was cleaved by 20 unitsof thrombin protease (GE Healthcare) at 4° C. overnight, and the proteinsolution was passed through a Ni-NTA column. The flowthrough wasconcentrated by Centriprep-10 (Millipore) to 20 mg/mL. Mixtures ofcognate ligand-complexes of CRALBP were separated on a Superose 6Increase SEC column (GE Healthcare) (FIG. 11A, FIG. 11B, FIG. 11C).

Example 10 Characterization of CRALBP-11-Cis-Retinal Homo-OligomericComplexes A. Size Exclusion Chromatography

Preparative and analytical SEC of CRALBP-11-cis-retinal homo-oligomerswas performed on HiLoad 16/60 Supersose 75 prep grade and on Superose 6SEC columns respectively (GE Healthcare, Little Chalfont, UK), bothattached to an AEKTA Purifier chromatography system (GE Healthcare,Little Chalfont, UK). Runs were performed in SEC buffer (20mMTris, pH7.4; 100 mM NaCl) at flow rates ranging from 0.5 (analytical) to 1.5ml/minute (preparative) at 6° C. Both SEC columns were calibrated usingcommercially available protein calibration kits (GE Healthcare, LittleChalfont, UK). Peak fractions representing monomericCRALBP-11-cis-retinal and homo-oligomeric CRALBP-11-cis-retinal werepooled and concentrated by Centriprep-10 (Millipore) to 20 mg/mL.

B. Negative-Stain Transmission Electron Microscopy

A sample of CRALBP-11-cis-retinal homo-oligomers at a concentration of0.3 mg/ml was adsorbed for 1 minute to parlodion carbon-coated coppergrids, which were previously rendered hydrophilic by glow discharge atlow pressure in air. After adsorption the grids were washed with threedrops of double-distilled water and stained with two drops of 0.75%uranyl formate. Electron micrographs were recorded with a Philips CM12transmission electron microscope operated at 80 kV and equipped with aMorada CCD camera (Soft Imaging System). Image analysis was performedwith the ImageJ image processing program V1.490 (NIH, MD, USA) (FIG.10).

Example 11 Characterization of CRALBP-9-Cis-Retinal Homo-OligomericComplexes A. Size Exclusion Chromatography

Preparative and analytical SEC of CRALBP-9-cis-retinal homo-oligomerswere performed on HiLoad 16/60 Supersose 75 prep grade and on Superose 6Increase SEC columns respectively (GE Healthcare, Little Chalfont, UK),both attached to an AEKTA Purifier chromatography system (GE Healthcare,Little Chalfont, UK). Runs were performed in SEC buffer (20mMTris, pH7.4; 100 mM NaCl) at flow rates ranging from 0.5 (analytical) to 1.5ml/minute (preparative) at 6° C. Both SEC columns were calibrated usingcommercially available protein calibration kits (GE Healthcare, LittleChalfont, UK). Peak fractions representing monomericCRALBP-9-cis-retinal and homo-oligomeric CRALBP-9-cis-retinal werepooled and concentrated by Centriprep-10 (Millipore) to 20 mg/mL (FIG.11A, FIG. 11B, FIG. 11C).

Example 12 Transcytosis by α-TTP-α-Tol Nanospheres Comprising α-TTPTrimers

α-TTP fractions corresponding to monomeric and tetracosameric proteinfrom analytic gel filtration were labeled with fluoresceinisothiocyanate (FITC) according to a PIERCE method previously describedby Horisberger (Horisberger, M. (1984)., Polak, J., Varndel, I. Ed.Elsevier: Amsterdam, p. 98). In brief, protein samples were transferredinto carbonate buffer (0.1 M, pH 9.0) for labelling using PD-10desalting columns (GE Healthcare, Little Chalfont, UK) previouslyequilibrated in the same buffer. FITC was freshly dissolved before usein anhydrous DMSO (1 mg/ml). The labeling reaction was started by adding50 μl of FITC DMSO solution to one ml of protein (1 mg/ml). The reactionmixture was incubated for 2 hours at 37° C. and stopped by removingexcessive FITC using a PD-10 column previously equilibrated in PBS (10mM phosphate, 138 mM NaCl, 27 mM KCl, pH 7.4). The labeled proteinsamples were finally purified by analytical SEC on a Superose 6 10/300GL column (GE Healthcare, Little Chalfont, UK) in PBS. Transferrin waslabeled by the same method and used as positive control in transcytosisexperiments. In order to demonstrate promotion of transcytosis byα-TTP-α-Tol nanospheres we used endothelial primary cells from humanumbelical veins (HUVECs). HUVECs were isolated from fresh umbilicalcords with the help of trypsin/EDTA according to a Miltenyi Biotecprotocol. Authenticity of endothelial origin was verified via positiveimmunofluorescence co-staining of Von Willebrand factor (vWF) and CD31.HUVECs were cultured in a Transwell system (permeable polyestermembranes with 0.4 μm pore size; Corning, USA) in Endothelial CellGrowth Medium (Promocell, Germany) comprising 100 U/ml penicillin and100 μg/ml streptomycin (PAN Biotech, Germany) with gelatine pre-coating(Sigma-Aldrich, Germany). Cells were allowed to form a tight monolayerwithin 7 days of culture while medium was changed every other day. Fortranscytosis measurements medium comprising 200 μg of RITC-dextran 70kDa (Sigma Aldrich, Mo., USA) and either 200 μg of FITC labeledmonomeric α-TTP, α-TTP-α-Tol nanospheres or transferrin (as a positivecontrol) was applied to the apical chamber, respectively. Transport wasmonitored by sampling 100 μl of basolateral medium at various timepoints (15, 30, 45, 60, 120, 180, and 240 minutes) after addition ofsamples to the apical chamber. Basolateral aliquots were subsequentlyanalysed for fluorescence with a Tecan infinite200 microplate reader(Tecan, Maennedorf, CH) at an excitation wavelength of 485 nm and anemission wavelength of 535 nm (FITC) followed by measurements at anexcitation wavelength of 545 nm and an emission wavelength of 590 nm(RITC), respectively. The CaCo-2/TC7 cell line (human colorectaladenocarcinoma cells; kindly provided by Dr. G. Lietz, NewcastleUniversity, UK) representing an epithelial cell model was used as anegative control in transcytosis experiments. CaCo-2 cells weremaintained in Dulbecco's Modi_ed Eagles Medium containing 4.5 g/lglucose, 4 mmol/l L-glutamine, 1 mmol/l sodium pyruvate, 100 U/mlpenicillin, 100 μg/ml streptomycin (PAN Biotec, Germany) and 20% (v/v)FCS (Gibco, Germany). CaCo-2 cells are widely used as an in vivo modelfor barrier and transport studies (Piegholdt S, et al., Free RadicalBiology and Medicine 2014 70:255-264; Kops S K, West A B, Leach J,Miller R H., The Journal of nutrition 1997 127:1744-1751; Levy E, MehranM, Seidman E., The FASEB Journal 1995 9:626-635). CaCo-2 cellsdifferentiate and form a tight epithelial monolayer in the sameTranswell system as described above within 10 days of culture.Transcytosis experiments were performed according to the HUVECexperiments. The rate of flux was calculated as previously described byFisher et al. (Fisher J, et al., American Journal of Physiology-CellPhysiology 2007 293:C641-C649). As a control for paracellular flux andas assurance for the formation of tight junctions, rhodamineisothiocyanate (RITC) dextran (70 kDa) was added simultaneously to theapical chamber in each experiment as tight junction control. The levelof paracellular transport by RITC dextran was measured in the samemanner as FITC-α-TTP, except that the RITC was detected at an excitationwavelength of 545 nm and an emission wavelength of 590 nm respectively.The different fluorescence behaviour of RITC and FITC has allowed forthe simultaneous analysis of the protein of interest and the dextrancontrol. Since dextran is not internalized at appreciable levels byendothelial cells, any accumulation of dextran in the basal chambercorrelates with paracellular flux (FIG. 12).

Example 13 Transcytosis by CRALBP-Cis-Retinal Nanospheres ComprisingCRALBP Trimers

CRALBP fractions corresponding to monomeric and homo oligomeric proteinfrom analytic gel filtration is labeled with fluorescein isothiocyanate(FITC) according to a PIERCE method previously described by Horisberger(Horisberger, M. (1984)., Polak, J., Varndel, I. Ed. Elsevier:Amsterdam, p. 98). In brief, protein samples is transferred intocarbonate buffer (0.1 M, pH 9.0) for labelling using PD-10 desaltingcolumns (GE Healthcare, Little Chalfont, UK) previously equilibrated inthe same buffer. FITC is freshly dissolved before use in anhydrous DMSO(1 mg/ml). The labeling reaction is started by adding 50 μl of FITC DMSOsolution to one ml of protein (1 mg/ml). The reaction mixture isincubated for 2 hours at 37° C. and stopped by removing excessive FITCusing a PD-10 column previously equilibrated in PBS (10 mM phosphate,138 mM NaCl, 27 mM KCl, pH 7.4). The labeled protein samples is finallypurified by analytical SEC on a Superose 6 10/300 GL column (GEHealthcare, Little Chalfont, UK) in PBS. Transferrin is labeled by thesame method and used as positive control in transcytosis experiments. Inorder to demonstrate promotion of transcytosis by CRALBP-cis-retinalnanospheres we use endothelial primary cells from human umbelical veins(HUVECs) isolated from fresh umbilical cords with the help oftrypsin/EDTA according to a Miltenyi Biotec protocol. Authenticity ofendothelial origin is verified via positive immunofluorescenceco-staining of Von Willebrand factor (vWF) and CD31. HUVECs is culturedin a Transwell system (permeable polyester membranes with 0.4 μm poresize; Corning, USA) in Endothelial Cell Growth Medium (Promocell,Germany) comprising 100 U/ml penicillin and 100 μg/ml streptomycin (PANBiotech, Germany) with gelatine pre-coating (Sigma-Aldrich, Germany).Cells are allowed to form a tight monolayer within 7 days of culturewhile medium is changed every other day. For transcytosis measurementsmedium comprising 200 μg of RITC-dextran 70 kDa (Sigma Aldrich, Mo.,USA) and either 200 μg of FITC labeled monomeric CRALBP,CRALBP-cis-retinal nanospheres or transferrin (as a positive control)are applied to the apical chamber, respectively. Transport is monitoredby sampling 100 μl of basolateral medium at various time points (15, 30,45, 60, 120, 180, and 240 minutes) after addition of samples to theapical chamber. Basolateral aliquots are subsequently analysed forfluorescence with a Tecan infinite200 microplate reader (Tecan,Maennedorf, CH) at an excitation wavelength of 485 nm and an emissionwavelength of 535 nm (FITC) followed by measurements at an excitationwavelength of 545 nm and an emission wavelength of 590 nm (RITC),respectively. The CaCo-2/TC7 cell line (human colorectal adenocarcinomacells; kindly provided by Dr. G. Lietz, Newcastle University, UK)representing an epithelial cell model is used as a negative control intranscytosis experiments. CaCo-2 cells are maintained in Dulbecco'sModified Eagles Medium containing 4.5 g/l glucose, 4 mmol/l L-glutamine,1 mmol/l sodium pyruvate, 100 U/ml penicillin, 100 g/ml streptomycin(PAN Biotec, Germany) and 20% (v/v) FCS (Gibco, Germany). CaCo-2 cellsare widely used as an in vivo model for barrier and transport studies(Piegholdt S, et al., Free Radical Biology and Medicine 2014 70:255-264;Kops S K, West A B, Leach J, Miller R H., The Journal of nutrition 1997127:1744-1751; Levy E, Mehran M, Seidman E., The FASEB Journal 19959:626-635). CaCo-2 cells differentiate and form a tight epithelialmonolayer in the same Transwell system as described above within 10 daysof culture. Transcytosis experiments are performed according to theHUVEC experiments. The rate of flux is calculated as previouslydescribed by Fisher et al. (Fisher J, et al., American Journal ofPhysiology-Cell Physiology 2007 293:C641-C649). As a control forparacellular flux and as assurance for the formation of tight junctions,rhodamine isothiocyanate (RITC) dextran (70 kDa) are addedsimultaneously to the apical chamber in each experiment as tightjunction control. The level of paracellular transport by RITC dextran ismeasured in the same manner as FITC-α-TTP, except that the RITC isdetected at an excitation wavelength of 545 nm and an emissionwavelength of 590 nm respectively. The different fluorescence behaviourof RITC and FITC allows for the simultaneous analysis of the protein ofinterest and the dextran control. Since dextran is not internalized atappreciable levels by endothelial cells, any accumulation of dextran inthe basal chamber correlates with paracellular flux.

1. A nanosphere comprising an equal number of: (i) a human SEC14-likeprotein, and (ii) a cognate ligand of said SEC14-like protein.
 2. Thenanosphere of claim 1, wherein said equal number is of 3 to
 60. 3. Thenanosphere of claim 1, wherein said human SEC14-like protein is selectedfrom (a) α-tocopherol transfer protein (α-TTP); (b) Cellularretinaldehyde binding protein (CRALBP); (c) Clavesin1 (CLVS1); (d)Clavesin2 (CLVS2); and (e) alpha-tocopherol transfer protein like(TTPAL).
 4. The nanosphere of claim 1, wherein said SEC14-like proteinis α-tocopherol transfer protein (α-TTP).
 5. The nanosphere of claim 4,wherein said equal number is
 24. 6. The nanosphere of claim 4, whereinsaid cognate ligand of said α-tocopherol transfer protein (α-TTP) is atocopherol.
 7. The nanosphere of claim 1, wherein said SEC14-likeprotein is Cellular retinaldehyde binding protein (CRALBP).
 8. Thenanosphere of claim 7, wherein said cognate ligand of said CRALBP is acis-retinol or a cis retinal.
 9. The nanosphere of claim 1, wherein saidSEC14-like protein comprises an amino acid sequence, wherein said aminoacid sequence of said SEC14-like protein comprises (a) an amino acidresidue selected from L and I on the position which corresponds to theposition 56 of SEQ ID NO:3; (b) the amino acid residue F on the positionwhich corresponds to the position 61 of SEQ ID NO:3; (c) an amino acidresidue selected from L, V, Q, H and Y on the position which correspondsto the position 63 of SEQ ID NO:3; (d) an amino acid residue selectedfrom W, Y, F and L on the position which corresponds to the position 67of SEQ ID NO:3; (e) the amino acid residue L on the position whichcorresponds to the position 70 of SEQ ID NO:3; or (f) an amino acidresidue selected from Y, V, F and H on the position which corresponds tothe position 74 of SEQ ID NO:3; wherein said amino acid sequence of saidSEC14-like protein comprises at least two of any one of said amino acidresidues of (a)-(f).
 10. A method of producing a nanosphere comprising,preferably consisting of, an equal number of: (i) a human SEC14-likeprotein, and (ii) a cognate ligand of said SEC14-like protein; whereinsaid method comprises the steps of (a) providing said SEC14-like proteinin an aqueous solution I, wherein the concentration of said SEC14-likeprotein in said solution I is 1 μM to 5 mM, and wherein the pH of saidsolution I is 6 to 9; (b) providing said cognate ligand of SEC14-likeprotein in a solution II, wherein the concentration of said cognateligand of SEC14-like protein in said solution I is 5 μM to 500 mM, andwherein the solvent of said solution II is a water soluble solvent; (c)generating a solution III by combining said solution I and said solutionII, wherein the ratio of the concentration of said SEC14-like proteinand the concentration of said cognate ligand of said SEC14-like proteinin said solution III is of between 4:1 to 1:4 (molar/molar), and whereinthe volume of said water soluble solvent in said solution III is ofbetween 0.5-8% (vol/vol); (d) allowing said SEC14-like protein and saidcognate ligand of said SEC14-like protein to assemble into a nanosphere;(e) separating said nanosphere from said solution III; (f) optionallypurifying said nanosphere.
 11. A method of producing a nanospherecomprising an equal number of: (i) a human SEC14-like protein, and (ii)a cognate ligand of said SEC14-like protein; wherein said methodcomprises the steps of (a) providing said SEC14-like protein in anaqueous solution I, wherein the concentration of said SEC14-like proteinin said solution I is 1 μM to 5 mM, and wherein the pH of said solutionI is 6 to 9; (b) providing said cognate ligand of SEC14-like protein inan aqueous solution II, wherein the concentration of said cognate ligandof SEC14-like protein in said solution I is 5 μM to 500 mM; and whereinsaid solution II comprises a detergent; (c) generating a solution III bycombining said solution I and said solution II, wherein the ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 4:1 to 1:4 (molar/molar); (d) removing said detergent from saidsolution III, wherein removing said detergent from said solution IIIallows said SEC14-like protein and said cognate ligand of saidSEC14-like protein to assemble into a nanosphere; (e) separating saidnanosphere from said solution III; (f) optionally purifying saidnanosphere.
 12. A method of producing a nanosphere comprising an equalnumber of: (i) a human SEC14-like protein, and (ii) a cognate ligand ofsaid SEC14-like protein; wherein said method comprises the steps of (a)providing said SEC14-like protein in an aqueous solution I, wherein theconcentration of said SEC14-like protein in said solution I is 1 μM to 5mM, and wherein the pH of said solution I is 6 to 9; (b) providing saidcognate ligand of SEC14-like protein in a solution II, wherein theconcentration of said cognate ligand of SEC14-like protein in saidsolution I is 5 μM to 500 mM, and wherein the solvent of said solutionII is a water soluble solvent; (c) generating a solution III bycombining said solution I and said solution II, wherein the ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 4:1 to 1:4 (molar/molar), and wherein the volume of said watersoluble solvent in said solution III is of between 0.5-8% (vol/vol); (d)allowing said SEC14-like protein and said cognate ligand of saidSEC14-like protein to form monomeric complexes consisting of one of saidSEC14-like protein and one of said cognate ligand of said SEC14-likeprotein; (e) separating said monomeric complexes from said solution III;(f) optionally purifying said monomeric complexes; (g) generating anaqueous solution IV, wherein said solution IV comprises said monomericcomplexes, and wherein the concentration of said monomeric complex insaid solution IV is 5 mg/ml to 50 mg/ml; and wherein the pH of saidsolution IV is 6 to 9; (h) allowing said monomeric complexes to formcrystals of said nanosphere.
 13. A method of producing a nanospherecomprising an equal number of: (i) a human SEC14-like protein, and (ii)a cognate ligand of said SEC14-like protein; wherein said methodcomprises the steps of (a) providing said SEC14-like protein in anaqueous solution I, wherein the concentration of said SEC14-like proteinin said solution I is 1 μM to 5 mM, and wherein the pH of said solutionI is 6 to 9; (b) providing said cognate ligand of SEC14-like protein inan aqueous solution II, wherein the concentration of said cognate ligandof SEC14-like protein in said solution I is 5 to 500 mM, and whereinsaid solution II comprises a detergent; (c) generating a solution III bycombining said solution I and said solution II, wherein the ratio of theconcentration of said SEC14-like protein and the concentration of saidcognate ligand of said SEC14-like protein in said solution III is ofbetween 4:1 to 1:4 (molar/molar); (d) removing said detergent from saidsolution III, wherein removing said detergent from said solution IIIallows said SEC14-like protein and said cognate ligand of saidSEC14-like protein to form monomeric complexes consisting of one of saidSEC14-like protein and one of said cognate ligand of said SEC14-likeprotein; (e) separating said monomeric complexes from said solution III;(f) optionally purifying said monomeric complexes; (g) generating anaqueous solution IV, wherein said solution IV comprises said monomericcomplexes, and wherein the concentration of said monomeric complex insaid solution IV is 5 mg/ml to 50 mg/ml, and wherein the pH of saidsolution IV is 6 to 9; (h) allowing said monomeric complexes to formcrystals of said nanosphere.
 14. A pharmaceutical compositioncomprising: (a) the nanosphere of claim 1; and (b) a pharmaceuticallyacceptable carrier.
 15. (canceled)
 16. The nanosphere of claim 7,wherein said cognate ligand of said CRALBP is selected from9-cis-retinal, 11-cis-retinal, 9,13-dicis-retinal, 9-cis-retinol,11-cis-retinol and 9,13-dicis-retinol.
 17. The nanosphere of claim 7,wherein said cognate ligand of said CRALBP is selected from9-cis-retinal, 11-cis-retinal and 9,13-dicis-retinal.
 18. The nanosphereof claim 7, wherein said cognate ligand of said CRALBP is 9-cis-retinal.19. The nanosphere of claim 7, wherein said cognate ligand of saidCRALBP is 11-cis-retinal.
 20. The nanosphere of claim 7, wherein saidcognate ligand of said CRALBP is 9,13-dicis-retinal.
 21. The method ofclaim 10, wherein said solution I comprises a salt.